kimchi & kraut

Passive House + Net Zero Energy + Permaculture Yard

Category Archives: Pretty Good House

Our Energy Bills

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The Logic Behind the Effort and Added Cost of Passive House

Passive House, as a building strategy, requires meticulous air sealing, along with ample amounts of insulation, carefully placed to eliminate or reduce the impact of thermal bridges through the building envelope. Once the air barrier of the building has been established, it requires mechanical ventilation to meet IAQ needs, along with high performance windows and doors to avoid undermining all of the air sealing and insulation.

Air sealing, water proofing, and thermal elements come together around a high performance window.

All of these elements together, if successfully managed and implemented, should achieve a building that requires significantly less energy to operate and maintain at comfortable temperatures than any conventionally built structure of similar size and shape.

The Visitor enjoying some early morning solar heat gain through our kitchen window.

With a ‘conservation first’ approach (i.e. extensive air sealing and insulation), the goal is to reduce total heating and cooling demand as much as reasonably possible (while maximizing occupant comfort), with the possibility of adding renewables like solar or wind as mostly an afterthought to further reduce, or eliminate entirely, the remaining energy demand of the structure. It also typically means going all electric, so in our case it meant no natural gas (the normal fuel source in our area for a furnace and a hot water tank).

So far, our 11 panel 2.9 kW system has been averaging between 3,500-4,000 kWh of solar production per year.

A Passive House structure, by design, should use significantly less energy than any conventionally built counterpart of similar size and shape. This includes lighting (normally assumes only LED fixtures will be used) and other plug-in loads (e.g. Energy Star appliances), as well as hot water (typically a heat pump hot water tank, or a newer product like Sanden or Chiltrix).

Unfortunately, these loads are relatively ‘baked-in’, even for an existing, conventionally built home. For instance, a hundred year old home could switch all of their light fixtures to LED bulbs, replace old appliances with new Energy Star rated models, and change out a gas-fired or a conventional electric hot water tank to a high-efficiency heat pump model. In effect, they’d have pretty much the same reduction in energy use as a brand new certified Passive House of similar size and layout for these particular sources of energy demand. As a result, the real opportunities for driving down energy use in a Passive House are in the heating and cooling loads (mainly due, of course, to the extensive air sealing and insulation levels).

On most days the 15,000 Btu head in our kitchen and family room handles all of the heating and AC needs for our entire house. We have two additional heads in our bedrooms (9k and 6k Btu respectively), but they’re rarely used apart from the coldest and hottest days of the year.

Although there has been some moving of the goal posts as the Passive House programs have evolved over time, they remain challenging targets to meet.

Here are the current PHI requirements according to Passipedia: Passive House Checklist

In the case of PHIUS, the requirements have gone through several iterations, for instance, PHIUS+ 2015, PHIUS+ 2018, and most recently a fairly dramatic change to a prescriptive track to seek certification with far less onerous levels of paperwork and data collection required.

Overall, regardless of which model is pursued, PHI or PHIUS, the intent is to dramatically reduce the overall energy use of buildings by emphasizing the importance of air sealing, insulating to levels that exceed current code requirements (in most cases), along with quantifying things like thermal bridges, heating and cooling demand, and peak heating and cooling demand. The issue of energy demand or energy use is further complicated by the distinction made between Primary/Source and Site Energy.

Additionally, there’s been a growing consensus regarding the need to incorporate renewables in these building strategies, both in terms of financial feasibility and in terms of further reducing (or even canceling out altogether) net energy demand. And while it’s true that Net Zero is fairly straightforward to achieve (assuming needlessly large PV arrays are not utilized as a short-cut), it does require a commitment to meticulous air sealing and quantities of insulation that, along with the in-depth energy modeling, unavoidably add cost to any construction budget.

Zehnder ERV, Rheem HPHW tank, radon pipe with fan, and battery back-up sump pump. Elements that support proper moisture management, IAQ, and HVAC needs.

The opportunity for significant energy reduction also correlates with the size of the project. Because of form factor ratios, the larger the project (assuming a compact form is mostly maintained) the more energy a structure stands to conserve. This is why larger institutional, multi-family projects, or corporate-sized projects stand to be the biggest winners when it comes to the purported benefits associated with Passive House energy conservation.

Outdoor heat pump compressor after the snow, but before the worst of the 2019 Polar Vortex.

If executed properly, low energy demand will mean considerable financial savings. These savings are cumulative, year after year, rather than just a one-off initial price break, with the added potential to increase should energy costs go up.

In addition, there is the potential for less upfront expenditures for HVAC equipment (less heating and AC demand — at least in theory — means smaller and more cost-effective equipment required). In our case, in climate zone 5, where we get cold, dry winters and hot, humid summers, this didn’t prove to be the case. Combining the cost of our heat pump and ERV reflected roughly what we would’ve paid had we built a conventional home with a high efficiency gas furnace with a humidifier attached (fairly typical system in our area). Either way, it would constitute roughly a $20,000 expenditure for a house under 2,000 square feet. The level of indoor comfort, however, should be vastly different between a conventional and a Passive House build.

Even though occupant behavior can derail some of these projected performance outcomes, assuming that homeowners or tenants are reasonably educated on the best way to enjoy and benefit from the Passive House details, especially the HVAC systems (normally this means commissioning units and then mostly leaving them alone in terms of settings), this should not be a stumbling block for most builds.

While all of this becomes more challenging with a smaller, more compact build like our 1,500 square foot single-family home, the possibility of significantly lowering energy demand is no less real, along with the cost savings. Not to mention the level of occupant comfort, which I personally feel is the main selling point of the Passive House building principles.

Some Background Information on Our Home

A quick summary of our build would include our blower door score of 0.2 ACH@50 (106 cfm@50), along with the following R-values for the structure:

R-16 Below the basement slab

R-20 Exterior of the basement foundation

R-40 Exterior walls

R-80 Attic

In 2019, our first full year of occupancy, with three of us (my wife, daughter, and myself) we had a total of just over 11,000 kWh of energy use. This included lighting, all other plug-in electricity demands (appliances, TV, computers, charging cell phones etc.), along with our HPHW tank and all of our heating and AC needs. It also included countless hours of power tool usage as I finished up interior trim, doors, along with some shelving and storage projects after we moved in. Record low temps during a Polar Vortex event in late January and into early February added to the total as well.

For 2020, a substantial increase in overall energy use might have been the expectation after the outbreak of COVID-19. Yet even after subsequent stay-at-home guidelines that began for us in March, we actually ended up at 10,446 kWh, a slightly lower annual number compared to the previous year. This lower total happened even with all three of us being home most of the time, with no breaks even for vacation time, outdoor activities that require some travel, or normal visits to family out of town.

If there’s a payoff in pursuing Passive House, it has to be in the combination of lower energy costs and increased occupant comfort when compared to a similar, conventionally built home or structure.

This lower number was in keeping with our usage during our first nine months (April-December, 2018). If the Polar Vortex was an anomaly (everyone hopes that it was), then most years going forward should be around 9,500-10,500 kWh for total annual demand. In part we think going over 11,000 kWH our first full year reflects just how significant a colder than normal winter can be on overall energy use in a Passive House, not to mention heating demand more generally (whether it’s a Passive House or not).

Moreover, for a family of three and a structure of this size with similar performance specs, it seems to suggest that our 3-4,000 kWh of annual usage per person is mostly ‘baked-in’. Meaning, in terms of occupant behavior, there’s not much we could do to further lower these numbers. Perhaps we could take fewer showers, cook less at home (stove and dishwasher), do less laundry, only ‘live’ from dawn to dusk (to avoid using artificial lighting at night), not do any woodworking or other DIY projects (use power tools off site?), and heat the home to only 60º F in the winter and cool to only 85º F in the summer. Obviously, these would be rather extreme measures to chase after the last final few kWh of energy use and, arguably, it wouldn’t be particularly meaningful apart from bragging rights should we end up with a lower annual total.

After all, it’s fair to ask what’s the point of the air sealing, insulation, and triple pane Passive House windows and doors, if it doesn’t produce a much more comfortable day-to-day living experience for those living inside the home or building? If simply chasing energy use were the main objective, reducing it no matter the consequences, then removing all the windows and doors and replacing them with continuous R-40 walls would be a good place to start, but hardly worth considering for obvious reasons. If there’s a payoff in pursuing Passive House, it has to be in the combination of lower energy costs and increased occupant comfort when compared to a similar, conventionally built home or structure.

In terms of unexpected surprises, really the only unanticipated energy use was the need for dehumidification on the hottest and most humid summer days of the year.

After our first summer in 2018, when part of the excess humidity was likely due to new construction moisture present inside the structure, we’ve been averaging about 30-40 days a summer, including a few random days in spring and fall, when the dehumidifiers are running intermittently. We set the units to 50% relative humidity, but normally they shut off around 55% based on gauges placed around the house. We try to keep the house under 60% RH. The risk for mold increases above 60%, but it’s mainly at that point when humidity levels make us feel noticeably uncomfortable.

Also, we didn’t think about the energy use associated with power tools for woodworking and arts and crafts projects. Without tracking it, we can only guess that it represents a few hundred kWh a year, rather than something in the thousands. We’ve been doing plenty of projects around the house our first three years, but still far less than what a full-time woodworking company would require. Even so, along with the potential for a EV charger, it’s something to think about when designing a new home or retrofitting an older one, especially if renewables are part of the equation and you’re trying to establish likely annual demand.

Actual Energy Use: Demand and Costs

The breakdown is as follows:

Based on our first 2.5 years in the house, we can expect 10-11,000 kWh of total energy use per year. Again, for some context, this is for a family of three, in a 1,500 square foot single story home that has a full basement.

In our first full year, 2019, we exceeded 11,000 kWh mainly due to the Polar Vortex. Compared to our first winter, along with numbers for this current season, it looks like the Polar Vortex added nearly 1,000 kWh of demand above a more typical January – March time period.

Over the course of our first 2.5 years (our first year was April-December), the numbers have been surprisingly consistent across seasons and month-to-month, regardless of our level of activity in the home (e.g. guests staying over, vacations away from the home, power tool use, etc.).

For instance, even in our first June, back in 2018, when the house was still drying out from new construction related moisture, and we felt compelled to start using two dehumidifiers to control excessive humidity (one in the kitchen and one in the basement), total energy use for the month was 616 kWh.

The following June, in 2019, we ended up with an even higher number, at 786 kWh of demand.

For June of this year, even with stay-at-home restrictions for COVID-19 in place, so a reasonable expectation might be for still yet higher demand, we actually ended up at a lower 605 kWh of use.

On a side note, it’s probably reasonable to assume COVID-19 had some impact on overall energy use for 2020, but after going through the numbers, it just seems unlikely that it contributed more than 500-1,000 kWh to our annual usage. We should have a better idea of its full impact once winter is over.

Presumably, without a granular study of day-to-day conditions, including day and night temperatures, along with relative humidity data, not to mention minor fluctuations in how we used the AC or how much laundry we were doing over these same three periods, it’s hard to explain this deviation with any level of certainty. Suffice it to say, we can expect June usage to normally be in the 600-800 kWh range. Obviously, a June in the future that experiences a heat wave like the one Chicago experienced in 1995 would likely drive the final number well over 800 kWh, but hopefully that remains a singular event rather than a more normal June.

In other words, even in a year where the weather remains milder than normal for a full 12 months, and we’re all exceedingly busy and rarely at home, our total energy use for the year, at best, will likely still end up in the 9,000-10,000 kWh range. And even if there was just one person living here, it’s hard to imagine they could keep total energy usage much below 4-5,000 kWh on an annual basis since so much of the demand is ‘baked-in’, as previously noted above.

Here is the monthly breakdown of energy use for the first full year we were in the home for 2019:

January: 1,738 kWh (includes 2019 Polar Vortex; following January was only 1,374 kWh)

February: 1483 kWh (the following year was 1,237 kWh)

March: 837 kWh (following year was 561 kWh — clearly a bitterly cold winter)

April: 681 kWh

May: 473 kWh

June: 786 kWh

July: 612 kWh

August: 608 kWh

September: 630 kWh

October: 812 kWh

November: 1,166 kWh

December: 1,237 kWh

Total energy use for 2019 was 11,063 kWh.

In this same period, our solar panels produced 3,863 kWh, so net demand for the year was 7,200 kWh (this requires some math using the billing statements from our utility company and the Enphase Enlighten solar app).

Our monthly bills for electricity in 2019 totaled: $1,075.89.

Because of our SRECs, which for us totaled $848 for the year (paid via quarterly checks), our net energy costs for 2019 were $227.89 (an average of $18.99 per month).

For comparison, numbers for 2020 were: 10,446 kWh of demand, while solar production for the same time period was 3,675 kWh, for a net energy demand of 6,771 kWh.

After SREC payments (again, totaling $848 for the year), our net total cost for 2020 was $189.36 (an average of $15.78 per month).

The SREC payments (these are based on a 5 year contract) reduced our annual cost by $848 each year, with a net average cost for our first two years of just $208.63 per year for all of our energy needs (a roughly $17.39 per month average).

Without any solar panels or SRECs, our electric bill would be roughly just under $1,500 per year based on current rates. By way of comparison, a new code-built home of the same size would likely pay more than twice this amount — an older home still more, assuming less air tightness and insulation, combined with a less efficient gas furnace for HVAC and domestic hot water.

It’s worth noting that as building codes tighten up their performance metrics, the difference in total energy demand between code-built and Passive House homes should continue to shrink. This assumes, however, that any number of ‘ifs’ are successfully overcome. For example, if air leakage is accurately measured (is there enforcement should the structure fail?). If a proper Manual J has been completed. If HVAC ducts are sized, installed, air sealed, and insulated properly. If insulation has been properly installed in appropriate quantities throughout the exterior walls and roof. If thermal bridges are avoided. If moisture (bulk and water vapor) is appropriately addressed and managed. This is a lot to get right, and it’s easy to get any number of things wrong, even with inspections and third party verification.

As pointed out earlier, since we’ve moved in we haven’t aggressively pursued trying to lower our energy demand. Instead, our approach has been to live ‘normally’, enjoying the benefits of the air sealing, insulation, and our HVAC set-up. We set and mostly forget our heat pump at 70º F in winter, 75º F in summer, in order to try and better understand ‘real world’ energy demand in a tight, well insulated and appropriately ventilated home of our size.

Hopefully some of this information can benefit others in the planning stages of their own Passive House, or Pretty Good House project. Moreover, in addition to WUFI analysis and PHPP, BEopt is another modeling option for figuring out energy demand and cost-effective design elements for a structure (new or old). The new calculator from PHIUS would also be a good place to start: PHIUS+ 2021

For anyone who wants an easy, initial test of their current home’s energy efficiency (EUI), a calculator like this one may be helpful: Energy Smart

Numbers for Heating and Cooling

In spring and fall when there’s less demand for heating or AC, our baseline monthly energy usage is below 500 kWh (this has been fairly consistent over the course of our 2.5 years in the home, even during COVID-19 when the three of us were home most of the time).

If this low demand could be maintained for much of the year, as it is in milder regions of the country like in parts of California, our annual usage could be cut by more than half (it wouldn’t require R-40 walls or R-80 attics to achieve either). Moreover, in these more temperate regions of the country with reduced insulation needs, and therefore less demand on HVAC systems, ‘green’ building programs like Passive House and Net Zero become even more attractive since they’re far more cost effective and easier to achieve.

In our case, summer months typically run about 600-800 kWh of actual usage, dependent on the number of days above 82º F when we typically find that we need to turn on the AC. Even on these days we will turn it off if there’s a sufficient drop in outdoor temps overnight, which allows us to open the windows (dependent on outdoor humidity or rain).

It might be worth noting that even though we thought we’d regularly open our windows whenever the weather was remotely nice, this hasn’t turned out to be the case. Between having to monitor indoor humidity levels, and the ability of our ERV to deliver continuous filtered fresh air (it’s shocking how quickly our fresh air supply filter turns black — within a month or two at the most), apart from the few days a year when the weather is perfect for opening windows, they mostly just stay shut. Much like Jim Gaffigan’s quip on seasons here in the Midwest, “Spring, that’s a fun day,” because the weather tends to be so mercurial there just aren’t that many days or nights when we feel comfortable leaving the windows open for extended periods of time.

On the plus side, it’s not uncommon for us to wait until there are 2-3 successive days where temperatures rise above 82º F before we feel the need to turn on the AC. In other words, there is some truth to the idea that Passive House buildings take some time to heat up or cool down based on outdoor conditions, although this can be quickly undermined by an ERV/HRV that’s set on high or in boost mode for long periods of the day (lots of cooking or showering, particularly relevant in the case of larger families, would make this a necessity) .

“Heating and cooling energy – that which is most reflective of the efforts of the design and construction process – is a small percentage of the total energy usage. As Andy Shapiro says, there is no such thing as a net zero house, only net zero families. Occupant choice matters hugely.”

—Marc Rosenbaum‘s report on South Mountain Company’s Eliakim Net Zero Energy Project

During the heart of winter, our total energy demand is in the range of 1,000-1,500 kWh per month. Even in January of 2019, with a Polar Vortex event, our bill still managed to stay below 2,000 kWh for the month. During this same week, however, we saw minimal benefit from our solar panels since they were covered by several inches of snow during the sunniest (and coldest) parts of the billing period.

These elevated kWh numbers during winter reflect just how much harder our Mitsubishi heat pump system has to work in order to maintain indoor comfort because of the Delta T between outdoor and indoor temperatures. And we can hear the difference: while in summer the system is virtually silent, in winter, especially as temps head towards zero, we can hear the compressor outdoors working to keep up. Compare this to summers: 75º F indoors vs. 95-100º F outside on the hottest days of the year, even though it’s significantly cooler for most of the summer, thus helping to explain the lower overall energy demand for AC usage in comparison to heating demand.

Cooling, unlike the demand for heating, is relatively comparable to what it would be in a conventional new build. In summer, the Passive House ‘thermos-like’ structure is mostly a hindrance rather than a benefit to keeping the interior comfortable. All the ‘free’ sources of heat in winter, e.g. south-facing windows on sunny days, body heat from the occupants, heat given off by computers, TVs, appliances, and even LED lights or our heat pump dryer, either thankfully don’t exist (in the case of south-facing glass because of sufficient overhangs) or they actively contribute (however small in some cases) to the overall cooling load.

In addition, because cooling loads are relatively low, and the efficiency of the mini-split heat pump is so high, even as the multiple indoor heads have no issue maintaining comfortable temperatures (we rarely notice the system — wall units or outdoor compressor — running in summer), it leaves us with a latent load that we need to address with two stand-alone dehumidifiers, indirectly adding to the overall cooling load.

So of our roughly 10-11,000 kWh per year of total demand, without an actual energy use monitor like TED on our main panel to establish exact numbers (a review of similar product options: here), it looks like just over 3,000 kWh is used for heating, with another 800-1,000 kWh used for cooling needs (at least in a typical year). In years where there’s a significant Polar Vortex event, or should a summer in the future experience an extended heat wave, then our numbers for heating and cooling are likely to hit 5-6,000 kWh of demand. With climate change, these numbers are invariably going to fluctuate or even grow depending on just how severe weather patterns become over the ensuing years and even decades.

Notes on Designing a Heat Pump System for Passive House

An issue worth considering, especially for those in the design stages of a build, is the added efficiency of a 1:1 set-up for heat pumps, meaning one outdoor compressor for each distribution head indoors (or air handler). There appears to be a growing consensus that this layout will offer added efficiency because of improved modulation over what has been a more typical set-up, like ours, which is a multi-zone system that has multiple distribution heads on a single compressor. It’s hard to imagine, at least in our case, that this impact could be more than a few hundred kWh per year, but worth exploring when having someone do a Manual J and S.

Additionally, we haven’t experienced any issues with the distribution heads in the two bedrooms (9k & 6k Btu’s respectively), either for heating or cooling, although concerns about the effectiveness of these undersized units in smaller bedrooms often comes up in discussions on how best to design and layout a heat pump system on Green Building Advisor.

When designing our system, I don’t remember this issue of 1:1 vs. multi-zone heat pump set-ups being discussed in any of the information I was able to hunt down, either in Passive House related books, or even online resources. I also didn’t come across discussion of the need for active, separate dehumidification while designing our build in 2016. These are just two examples demonstrating that Passive House is still actively evolving as a ‘green’ building program (potential overheating in winter and shoulder seasons would be a third example).

A cautionary tale for designers, as well as building owners, to guard against hubris as the construction drawings develop or when the details are finally executed on a construction job site. Other issues may arise with Passive House builds in the coming years, so it’s worth considering potential unintended consequences before finalizing details. Today’s solution may be someone’s costly headache tomorrow.

Additional Solar Panels to Achieve Net Zero?

Based on what we’ve been paying for energy in these first 2.5 years, we don’t feel compelled to add more solar panels at this time. Should the SREC’s dramatically fall in value with a new contract, or disappear altogether, it might encourage us, at that point, to purchase more panels for the roof. But even so, at less than $90 per month, even without the SREC’s, it makes our energy bills a relatively painless expenditure (roughly equivalent to one nice restaurant dinner for the three of us, or still less than what we pay on a monthly basis for things like coffee, breakfast cereals, and milk). Put another way, averaging around 3,500 kWh per person of demand, whether with or without the solar panels and our SRECs payments, our monthly energy bill is typically cheaper than a single visit to the grocery store.

Because of the effort and money expended upfront for air sealing and insulation, all while trying to carefully manage window placement and HVAC layout successfully, we’ve managed to whittle our energy costs down to something highly affordable and resistant to significant cost increases. This should remain true, regardless of what’s happening in the market in terms of prices for natural gas, coal, or nuclear power (i.e. the major sources of power in our region, here in the Midwest). Worst case scenario, we add additional solar panels to get to Net Zero or even Net Positive in order to cancel out what remains of our monthly energy bill. This would require an additional 7-8,000 kWh of annual solar production, or roughly three times what our current system produces.

In our specific case as a household — averaging between 3,500-4,000 kWh of solar production per year (this amounts to nearly 40% of our annual demand), combined with SRECs — we nearly end up at Net Zero, at least in terms of total cash spent for energy (arguably the most important — maybe the only — metric that homeowners ultimately care about; whether it’s the total cost to build a new home, or in terms of the annual energy bill). As a result, there’s not much financial incentive to purchase additional solar panels to achieve absolute zero energy consumption (this is in site energy terms only). The fact that this all comes with a house that’s extremely comfortable and quiet to live in, regardless of season or room, makes our home only that much more valuable to us.

Passive House + Net Zero?

In addition to designing for Passive House, there is the question of Net Zero or even Net Positive buildings. While Passive House strategies eliminate a significant portion of overall demand by requiring a significant outlay of upfront funds for air sealing and insulation, once this pill has been swallowed, it’s normally cost-effective to incorporate renewable energy of some kind to cancel out the expense of the remaining energy bill.

A quick side note: An excellent resource, one that I found only as our build was coming to an end, is William Maclay’s book The New Net Zero. It contains a wealth of information, but, in particular, many specific construction details vividly illustrated. This is especially valuable for DIY builders, or even seasoned professionals, when evaluating all the possible elements of roof-wall-foundation assemblies.

Also worth noting, if this approach (Passive House + Net Zero) were adopted on a national level, including renovations, it would eliminate a large portion of aggregate energy demand, thus having a meaningful impact on greenhouse gas emissions and global climate change (up to 40% for construction and existing buildings).

Based on what we know at the moment, a combination of approaches — including Passive House building principles, Zero Carbon goals, and the use of renewables — could be the way out of the climate crisis over the long haul. In addition, if adopted as part of building codes, it could mean properly training the next generation of tradespeople (like European-style apprenticeship models, thereby also improving the build quality) while also being a tremendously effective jobs program.

Beyond Net Zero, or even Net Positive, in regards to energy demand, there is increasing awareness about carbon emissions more generally, and the variety of ways to radically reduce or sequester it, including the choice of building materials (for new construction or retrofit projects) or even how we decide to landscape our yards.

Passive House Cost Premium

Unfortunately, due to relatively inexpensive utility rates here in the Midwest, even though Passive House (or Pretty Good House) offers a significant reduction in energy costs if done well, when considered as a percentage of household income the numbers may appear much less impactful or motivating when faced with line items in a build budget for things like air sealing and levels of insulation that far exceed building code requirements.

In our case, the annual energy savings compared to something code-built would likely be in the $2-3,000 range. Fairly significant, but if the purchase price of the home is $500,000 – 1,000,000+ (fairly typical here in the Chicago suburbs for new construction) then even a $100,000 savings over the course of a 30 year mortgage may not convince someone to move beyond conventional construction practices (particularly if they have their heart set on a long list of high-end finishes and appliances). The upfront costs associated with meticulous air sealing and added levels of insulation — if not viewed as an investment in build quality — will likely appear frivolous to the average consumer.

“One of the issues we face here is the fact that energy is cheap, like most things in the Midwest. We don’t have the financial burden placed on us that the coasts do—real estate-wise and energy-wise. So there is not much enthusiasm around green building on a financial level; it’s almost always an ethical issue. The people who are interested want to do a good thing for the environment, as opposed to saving money on their utility bills. Another thing is that people are accustomed to discomfort—we have drastic and frequent temperature swings. It’s really humid in the summer and freezing in the winters, when drafty windows are just accepted. They are used [to] it, so it is hard to sell them on high-performance windows to be more comfortable; or taking measures to keep a basement from being wet—they just aren’t concerned about it. There’s a complacency that we fight against; there’s not enough financial gain to incentivize making upgrades.” — Travis Brungardt, GBA Q&A

Looking solely at upfront costs is likely to discourage most prospective homebuyers from pursuing Passive House (or even Pretty Good House in many cases), whereas looking at the cost of ownership, including the cost of monthly utilities, produces a more accurate comparison (note, however, this assumes the homeowner can stay put for at least the next twenty to thirty years).

A cost of ownership calculation should also acknowledge less maintenance costs year-to-year since, if the structure is detailed well, it should experience far fewer issues (none ideally), especially damage caused by bulk water intrusion, mold, or even air leakage. Granted, it may take a decade or more before this kind of damage is found in a conventional home, but when it is, it’s rarely (if ever) inexpensive to properly correct.

Hard Choices

As a culture, we have been in a similar place before. One quick example would be automotive engineering applied to car safety. In terms of perspective, if you get the balance between cost and safety wrong when evaluating value, then seat belts, air bags, and better designed bumpers might seem like misspent dollars.

“Nader argued that Detroit willfully neglected advances in auto safety, like roll bars and seat belts, to keep costs down… But using [seatbelts] was strictly voluntary. And many Americans didn’t want to.”

— Daniel Ackerman, Before Facemasks, Americans Went to War over Seat Belts

In a similar vein, the American consumer has been taught by the market, realtors, and builders to believe cost per square foot is the gold standard of value. As a consequence, little emphasis is placed on building science basics such as air tightness, proper moisture management, thermal performance, or indoor air quality. In layman’s terms, this means the average American home is leaky, parts of it have likely been damaged by bulk water or mold, and it’s uncomfortable in terms of indoor temperatures and humidity, all while delivering subpar air quality to its occupants.

In terms of quality construction and ‘green’ building (Passive House or not), the hard truth is there really is no free lunch (not even renting: rentcafe). Quality, of any kind — finishes, proper moisture management, occupant comfort, even reduced energy bills — has its price, but only those who recognize its value will be willing to pay for it.

Regardless, as homeowners we either pay upfront for the air sealing and insulation, along with high performance HVAC for better IAQ, or we pay monthly (and perpetually) in the form of higher energy bills (this normally comes with less occupant comfort) and far inferior IAQ. Either way, the money is going to be spent, it’s just a question of when (upfront vs. long term month-to-month) and for what (air sealing and insulation vs. mediocre systems and underwhelming outcomes that require costly maintenance over time).

As with car safety in the past, depending on one’s point of view, the answer to these kinds of construction and homeownership options are either obvious or nonsensical. Nevertheless, regardless of the path taken — conventional construction or some version of high performance — no one’s wallet will remain closed for long.

Passive Solar: The Beauty of Light

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Does Passive Solar Design Still Make Sense?

Our ‘green’ building adventure began in 2013 when I came across various Passive House and high performance projects in Prefabulous + Almost Off the Grid by Sheri Koones. The red house featured on the cover and built by GO Logic, in particular, seemed like a striking departure from conventional homebuilding as practiced in the US.

In its overall shape it echoed an earlier project that I only became aware of later, the Smith House in Illinois by Katrin Klingenberg.

Arguably, in both cases, these homes have too much glass on their south elevations, both in terms of potential overheating of the interior and in purely aesthetic visual terms. Nevertheless, using south-facing glazing to bring in the sun during the winter months while getting some Btu’s of free heat made a lot of sense to us, especially in a heating dominated climate like ours here in the Chicago area.

By the time construction began, we had settled on what seemed like a significant amount of windows and a kitchen door for our south elevation. We felt the layout would be an appropriate amount both in terms of passive solar heating and aesthetics, in addition to daylighting needs.

Moreover, by addressing the main weaknesses of the original Passive Solar movement of the 1970’s, namely the lack of air tightness and sufficient levels of insulation, we hoped that we could strike a balance between enjoying the seasonal movement of the sun in and out of our home while mostly eliminating the risk of overheating, even during shoulder seasons (spring and fall).

Since our build, however, there appears to be growing concern about just how effective this design strategy really is for Passive Houses or high-performance homes more generally. In effect, are the potential savings on a heating bill really worth the risk of temporarily overheating interior spaces?

Joe Lstiburek, of Building Science Corporation fame, puts it bluntly when quoted in a GBA article regarding the use of high SHGC glass:

“Don’t bother with the passive solar. Your house will overheat in the winter. Yes, you heard that right. Even in Chicago. … You should go with very, very low SHGCs, around 0.2, in your glazing. If this sounds familiar to those of you who are as old as me, it should.

“We were here in the late 1970s when ‘mass and glass’ took on ‘superinsulated.’ Superinsulated won,” Lstiburek continued. “And superinsulated won with lousy windows compared to what we have today. What are you folks thinking? Today’s ‘ultra-efficient’ crushes the old ‘superinsulated,’ and you want to collect solar energy? Leave that to the PV.”

Clearly, he’s not entirely wrong, especially when some of the early failures in the Passive House movement revolved around this very issue of overheating. If you were an early adopter of the Passive House concept, especially if you were the homeowner, and you ended up with comfort issues because of too much glass on your southern facade it certainly would make you doubt the purported precision of the Passive House energy modeling.

Nevertheless, with careful planning, it is possible to avoid this issue of overheating while still getting to enjoy most of the benefits associated with passive solar design. In our case, this meant limiting windows on the north side (net energy losers) to just our daughter’s bedroom, while glazing on the east side shows up only in a small area of our front door.

Small amount of glass in our front door offering some daylighting benefit for our entry area.

In addition, we avoided any potential for overheating from our west-facing windows by using self-tinting Suntuitive glass in our master bedroom and family room. This glass can fluctuate in its SHGC between (.08 – .18) depending on whether in its fully tinted or clear state (varies depending on surface temperature of the glass).

West facade with self-tinting Suntuitive glass.

With the other three sides of the house accounted for, we were able to concentrate all of our attention on the best window layout for the south side of the house. The utility room, which is on the southeast corner of the house, only really needed a small window, so we went with a single 3′ x 5′ unit. In the kitchen, the window above the sink was already going to be limited because of the lower cabinets, and was mainly for a view while doing dishes. This unit ended up being 4′ x 5′. For the kitchen door we went with a mostly glazed door with privacy glass, which has worked out well as it lets in an abundant amount of daylight while it’s never caused any issues with overheating.

The real challenge was getting the family room window on the south side of the house sized correctly. The temptation was to go too large since we had the space to do it. Instead, we wanted to retain some empty wall space for artwork on either side of this window, while also remembering that even the best window is still a lousy wall (e.g. R-40 wall vs. R-6 window).

In the end, we decided to go with a 3′ x 9′ window in our family room, slightly smaller* than the units on the west facade with Suntuitive.

{*7-27-20 Correction: I messed this up. The dimensions weren’t different between the south-facing family room window and the west-facing windows with Suntuitive — it was a height off the floor change. For the south-facing family room window we went slightly higher, 32″ off the finished floor, in order to gain a little more privacy, while on the west-facing windows we maintained a lower height of 27″ off the finished floor to maximize our views out and into our backyard. This 5″ difference may not sound like much, but it has a dramatic effect in terms of overall views and perspective when standing at these windows.}

In terms of wall area on our south facade, the windows and kitchen door account for just under 15% of the total, so not a crazy amount, and obviously nowhere near the amount of glass in a curtain wall.

The Sun’s Path Month-to-Month

For those who haven’t directly experienced a space that utilizes passive solar design principles, it may be helpful to see in photos what exactly this effect means month-to-month in a real home.

In our case, we have a long interior wall that runs east-west along the longest axis of our home. This wall effectively separates the private areas to the north (bedrooms and bathrooms) from the public areas to the south (family room, kitchen, and utility room). For context, this long wall stands almost 16 feet from all of the south-facing windows.

In our kitchen and family room, here’s what the sun looks like near midday in January:

jan fmly rm
Sun in January, slowly moving away from the back wall (at right) that runs east-west along the longest axis of the house.
jan ldry rm
Sun pouring into the utility room in January.

By the middle of February, the sun is already making its way towards the windows, barely able to reach the family room couch, while it still adds plenty of sunshine and warmth to the kitchen and family room areas:

sun feb fam
Sun in mid-February.

By the Spring equinox, the sun has continued its slow march across the family room floor towards the south-facing windows:

sun mar fam
Sun in March.

In the basement, with the help of two large south-facing windows (each 4′ x 4′) and our oversized window wells, the sun is making the same progression as it brightens up the below grade space:

sun mar base
Basement in mid-March.

Although we chose to forego any windows on the east side of our house, mainly for privacy and energy loss reasons, the small amount of glass in our front door still allows our entry area to be bathed in beautiful early morning light without contributing a significant amount of heat gain:

sun mar morning east
East-facing entry area flooded with morning light from the minimal glazing in the front door.

The seasonal path of the sun can also be marked on the exterior by its progress up or down the facade of our south elevation. By mid-March you can see the shadow line formed by our substantial roof overhang beginning to make its way down the siding — at this point, just above the windows and kitchen door. This invisible ‘curtain’ will cover the glass in the windows entirely by the end of June, completely denying the heat of the sun direct entry into the structure.

sun ext mar
South elevation in mid-March. Note the shadow line just above the windows and kitchen door.

Even in April the sun is mostly denied entry; reduced to a sliver of light hitting the wood floor in the family room:

sun apr fam
Family room in April.

In June, by the time of the summer solstice, the sun has been pushed outside completely, limited to the metal sill pans on the exterior of the windows.

Our south elevation during the rough framing stage. Layout from left to right: family room, kitchen door, kitchen window, and utility room.

With significant and thoughtfully placed windows on the south side (combined with a substantial roof overhang), we’re able to enjoy views to the outdoors year-round, allowing us to maintain an unbroken connection to nature in our yard, without any of the heat or glare normally associated with the summer sun. It also means we don’t need to bother with curtains or other window treatments, or the hassle of managing when they should be opened or closed.

Also, since the transition from winter (welcoming the sun in) to summer (denying the sun entry) has proven to be seamless, we’ve been able to avoid installing any curtains or window treatments in order to hide from any periods of unwanted sunlight. Basically, this invisible ‘curtain’ effect of passive solar design means we enjoy all the benefits of window treatments without any of the hassles (routine opening and closing, cleaning, or maintenance and repair), all while maintaining an unobstructed view of the outdoors. This is especially rewarding during the long winter months when starved for sunlight and extra warmth, but equally pleasurable as life begins to hum in the yard with the return of spring and summer.

In the photo below, the family room window (at left) and the kitchen door are protected from the heat of the sun by the roof overhang. The window on the back wall (facing west) is protected by self-tinting Suntuitive glass, which also allows us to enjoy unimpeded views of our backyard without the need for curtains or window treatments, even on the sunniest and hottest days of summer.

sun june fam
Family room in June with no direct sun allowed entry into the space.

On the exterior, by the middle of June, this shadow ‘curtain’ has fallen over the entire face of the south-facing windows, denying the sun entry into the home where it could cause unpleasant glare and unwanted heat gain (these windows have a SHGC of .54), which would needlessly increase cooling loads for our Mitsubishi heat pump system, while also reducing overall occupant comfort.

Around the summer solstice in June, this is what the set-up looks like outdoors:

Southwest corner of the house around the summer solstice.
A second view of this ‘curtain’ effect; this time from the southeast corner of the home.

This effect is also visible from the interior while looking out the south-facing windows. With a substantial roof overhang the sun can barely reach the metal sill pans by the middle of June:

sun june util
Utility room window in the middle of June. Note the sun hitting the outside edge of the metal sill pan.

In June, the sun is able to get slightly deeper inside the home in the basement — in this case managing to hit the surface of the window stool or sill.

sun base june

Even in the heart of the summer, the sun is still denied direct access to the interior spaces on the main floor:

sun july fam
Family room in July. The sun remains outside.

A second look at the metal sill pan from the utility room window, this time in July:

sun july util

After slowly making its way back into the south-facing living areas, by November the sun is once again approaching the back wall in the family room and kitchen:

sun nov family
Family room by mid-November.

Even though the utility room window is a relatively modest size (3′ x 5′), it provides ample daylight and plenty of warm sunshine over the course of our long winter months:

sun utility nov
Sunlight spilling out of the utility room by mid-November.

Here’s another view of the sun exiting the utility room on its way to the back wall in the main living area:

sun utility nov 2
Sun in mid-November.
sun nov kitch
Sun hitting the kitchen countertops in November, bathing the space in a warm glow.

By late December, around the winter solstice, the sun is finally able to hit the back wall in the main living area, maximizing the amount of direct sunlight that enters the house:

sun dec family mbr
Sun during the winter solstice, at the doorway to the master bedroom.

sun kit dec
In late December, the sun hits the back wall where the family room meets the kitchen.

sun dec utility barn door
Sunlight from the utility room window hitting the barn door in the main living area.

Even in the basement, where it’s more difficult for the sun to make its way into the space, with our oversized window wells and two large windows the sun manages to get very close to the center of the space just in front of the structural beam. This light pouring in helps keep us connected to the outdoors, mostly eliminating the cave-like feel normally associated with many below grade spaces. Even on the coldest days in winter, this daylighting effect makes the basement a warm, inviting space.

basement bfws sun
Sunlight entering the basement in mid-December.

Some Final Thoughts

We were expecting to enjoy the seasonal movement of the sun, watching it progress in and out of the main living space, warming us in the winter while also helping to moderate summertime AC demand. One unanticipated surprise, however, is how effective our window layout has been in maintaining a high level of daylighting, even on the grayest of overcast days.

Short of a menacing thunderstorm that turns the skies gray-black, we almost never have to turn on lights during the day. For instance, in the photo below it has snowed overnight, and the skies are an unrelenting blanket of gray. Nevertheless, because daylight has ample means for entering the living space, no artificial light is necessary. Note, too, in the background, how clear the Suntuitive glass is when not in its fully tinted state.

The kitchen door, because it consists mostly of privacy glass, contributes a great deal to this daylighting effect — both in summer and winter — and we’re extremely happy we didn’t choose a more opaque door style.

Another side benefit in this regard is how the porch light outside this glass-filled door also acts as a de facto night light for the kitchen — its soft, but effective, glow makes it easy to navigate around the space in the middle of the night without having to turn on any interior lights.

cloudy day still light
Even on a cold, gray winter day the windows allow in a great deal of daylight, dramatically improving the overall livability of the space while allowing us to keep the lights turned off.

One final, unanticipated surprise is how much the house is flooded with light on cloudless nights when there’s a full moon. The moonlight creates a soft, beautiful source of light as it falls across these interior spaces.

In terms of shoulder seasons, when sunlight still has some access to the interior but outdoor temperatures are mild or even occasionally warm, we haven’t really noticed a problem. In spring, if outdoor temps should reach the 70’s during the day it is frankly welcomed with open arms, as we’re starved for warm sunshine at winter’s end. In the fall, if there’s an occasional too warm day, we simply open a couple of windows. So far we’ve never had to turn on the AC in October, for instance.

If there’s any failure in our set-up, it would be the family room couch. From the end of December until the end of January, if it’s a sunny day, regardless of how cold it gets outside, sitting on the couch is uncomfortable, if not impossible. Sitting in shorts and a tank top would be the only way to make it remotely comfortable.

Thankfully, we’re almost never on the couch during this time, so it’s never been a problem for us. Having said that, if this family room were dedicated office space and I needed to be sitting at my desk from 10am-2pm, it would be extremely uncomfortable. This is a good example of how carefully not just an overall floor plan needs to be designed, but how even individual spaces need special attention, in particular for year-round HVAC comfort based on how occupants are actually going to be using the space.

Overall, we’ve been very pleased with the layout of our windows and their ability, in conjunction with the roof overhang to the south, to allow in ample amounts of sunlight during the colder months while still being able to keep it out on the hottest days of the year. With detailed planning, our experience suggests that designing living spaces for a real passive solar benefit is still a worthwhile goal.

Although it may be safer to ignore this design strategy altogether in the hottest climates (simply designing to keep the sun outside year-round may be the better option, which would include the use of low SHGC glass as Lstiburek recommends), passive solar has proven to be a great source of enjoyment for us, particularly during our winters here in Chicago, which tend to release their grip too slowly and ever so begrudgingly.

If given the chance, we would definitely design our house again with these passive solar techniques in mind.

Completing our Wall Assembly: Rockwool Batts, Intello, and Drywall

4

Insulation for Exterior Walls

Once Wojtek and Mark were done installing our continuous insulation on the exterior side of our Zip sheathing (4″ of Rockwool Comfortboard 80), including the first layer of battens (no more errant fasteners through the Zip to worry about), I was able to move inside and begin installing Rockwool Batts (R-23) in our 2×6 wall framing.

Once we had moved on from our first builder, and after reading up on the available options for insulation, we decided to invest in Rockwool insulation, both the rigid Comfortboard 80 on the exterior of our sheathing and the Rockwool batts for inside our stud bays. Although more expensive, particularly the Comfortboard 80 for continuous insulation (used rigid foam would’ve been substantially less expensive), we felt that many of its properties made it worth the added cost.

In particular, by helping our wall assembly to be vapor-permeable (or vapor open), we felt the Rockwool could help mitigate any mistakes, should they be made, in the wall assembly details. This being our first build acting as a GC, we wanted to add some margin for error wherever we could find it.

More details on our wall assembly and how we finalized details, including our desire to maintain a high level of IAQ, can be found here: Wall Assembly

For environmental reasons, one of our goals was to try and be as “foam free” as possible throughout the build. In addition, beyond just this issue regarding the use of foam (in all its forms: rigid board and sprayed varieties alike), there’s increasing awareness about the carbon footprint of our structures, not to mention the total carbon footprint of our daily lives.

At any rate, if I had it to do over, I would at least seriously consider using reclaimed rigid foam for our continuous insulation over the sheathing (both for the potential cost savings and its status as a reclaimed material otherwise headed for a landfill), understanding that it does reduce a wall’s ability to dry to the exterior. As others have noted, using reclaimed rigid foam in this way may be the best, or “greenest”, use of foam insulation until the construction industry hopefully moves beyond its use altogether as better options become more viable (e.g. wood fiber insulation).

Here are some resources for reclaimed rigid foam:

http://insulationdepot.com/

https://www.reuseaction.com/sales/foam/

https://www.greeninsulationgroup.com/

https://www.repurposedmaterialsinc.com/polyiso-insulation/

I would also consider using dense pack cellulose in the 2×6 walls instead of the Rockwool batts if I could find an installer I was reasonably certain could do the work properly. During construction it felt safer to use my own labor to install the Rockwool batts, thus avoiding the possibility of any gaps in the wall insulation. I was hoping to offset the cost of the batts with my free labor, plus I just enjoyed doing the work. Had we gone with the dense pack cellulose, it would’ve been something I couldn’t do on my own (no equipment or training).

lights on in base 4 rockwool
Basement ready for Rockwool batt insulation.

Installing the Rockwool batts is fairly easy and satisfying work. They’re much easier to work with than fiberglass batts, which are horrible on your skin and tend to flop around as you try to get them into place. While the Rockwool also produces some irritating fibers when it’s cut (and requires a dust mask like fiberglass), I found that a shower easily washed them away. Wearing long sleeves during installation also easily mitigates this issue.

base knee wall w: rockwool going in
Insulating the exterior wall in what will be the basement stairwell.

Also, the fact that the Rockwool batts have a friction fit means they don’t require any additional staples or netting to get them to stay put once installed.

Because of the friction fit, it’s also easy to tear off small pieces to stuff into irregular shaped voids should the need arise.

rim joist w: and w:out rockwool
Basement rim joist without and with Rockwool batt insulation.

Like the Comfortboard 80, the batts can have some variation from one piece to another, with a change in the amount of density clearly visible. With the Comfortboard 80, this was significant enough that we avoided using the worst pieces, meaning those with the least amount of density (these pieces felt thinner and sometimes even crumbly). Although this inconsistency was still present in the batts, I managed to use almost every piece, saving the least dense pieces for use in some interior walls for sound attenuation (more on this topic below).

base kneel wall corner rockwool
Corner of basement with knee wall and rim joists insulated with Rockwool batts.

Overall, we were happy with the Rockwool batts, and would definitely use them again should dense pack cellulose not be a viable option. They’re also ideal for a self-build since anyone who’s reasonably handy can install them should they have the time available during construction.

rockwool around base beam
Rockwool batts packed into gaps around the basement steel beam.

In conjunction with the Intello that would eventually be installed over the 2×6 framing members and the Rockwool batts, we also used Flame Tech putty pads to air seal behind every outlet and light switch box. I had seen them used in a Matt Risinger video for sound attenuation:

The other option would’ve been to use airtight junction boxes. Here are a couple of examples: Small Planet Supply and 475HPBS.

In order to limit issues with all the air sealing I was doing, I tried to stick with products my subcontractors already used everyday. As a result, since my electrician wasn’t familiar with airtight junction boxes, I opted instead to come in after he had everything installed and apply the putty pads. I found installing them to be straightforward and pretty quick.

box label putty pads

The putty pads are attached to release paper. Once the paper was removed the pads were easy to mold around each outlet and light switch box.

label putty pad
Acoustical putty pads purchased on Amazon.

Here’s a completed outlet box:

putty pad on outlet
Putty pad molded around every outlet and light switch in exterior walls.

The trickiest area to detail for the walls was at the ceiling and wall junction. In our case, the roof trusses sit on 2-2×6’s turned on their sides, which sit on top of the wall’s double top plate. The 2-2×6’s create space for our service cavity under the bottom chord of the roof trusses.

extoseal-encors-as-gasket
2-2×6’s on edge, sitting on double top plates. Extoseal Encors acting as gasket once taped from the exterior face of the Zip sheathing over the top of the 2-2×6’s, thus completing an air sealed connection between the exterior (Zip sheathing) and the interior before roof trusses are set in place. More details here: Roof Details

Before cellulose could be blown into the attic, we installed Intello to the bottom chord of the roof trusses. At all outside edges the Intello was carried from the roof trusses down over the double top plates of the walls, anticipating the Intello eventually being installed on the walls, which required a connection point between the Intello on the ceiling and the Intello on the walls.

ceiling-wall b4 Intello - Rockwool
Ceiling and wall areas before installing Intello on the bottom chord of the roof trusses and Rockwool batts in the walls.

After the Intello was installed on the ceiling, a service cavity (or service core, or service chase) was created with 2×6’s screwed to the bottom chord of the trusses through the Intello.

string between junction boxes to make sure they're straight
Service cavity with 2×6’s attached to trusses through the Intello. More info on the service cavity here: Ceiling Details.

This gap was going to be a dedicated space for lighting and the 3″ Zehnder tubes of our ERV (as things turned out, we didn’t end up needing this space for the Zehnder tubes).

bare trusses - intello - intello w: single layer CB 80 - service chase
Intello coming down from the roof trusses to cover the double top plates on the wall.

Before installing the Rockwool batts in the walls, I was also able to fill this gap created by the two 2×6’s on their side that sit on top of the double top plates with leftover pieces of Comfortboard 80. The first piece of Rockwool fit snug inside the gap, while the second piece was attached to the first with some plastic cap nails and the friction supplied by the 2×6’s forming the service cavity. Some additional holding power was added at the gable ends by utilizing drywall clips (visible in the photo below):

intello onto top plates
Connecting Intello to top plates with a strip of Tescon Vana tape, creating a clean and solid surface for the eventual Intello on the walls.

The drywall clips were helpful in lending support to drywall anywhere that adding solid blocking would be time consuming or a physical challenge.

nailer for ceiling drywall
These drywall clips worked great in places where the sheetrock needed additional support.

Even though we utilized a 12″ raised heel roof truss, and we had 4″ of Rockwool on the exterior of our Zip sheathing, it was important to fill this gap created by the service cavity to make sure our thermal layer was unbroken around the perimeter of the house (4″ Rockwool on the exterior, 5 1/2″ Rockwool in the stud bays). The outside edge of the roof truss is also the most vulnerable to ice damming, so having the 4″ of Rockwool Comfortboard 80 directly below this area where blown-in cellulose would be installed offers some additional thermal performance to the attic insulation.

Another view of this area where roof truss meets the 2-2×6’s standing on their side, creating a gap between the bottom chord of the roof truss and the top plates on the wall below.

sealed top of wall from inside
Roof truss on 2-2×6’s turned on their sides, which have been sealed with Pro Clima tapes. HF sealant completes the airtight connection between the Zip sheathing and the 2-2×6’s.

If I had it to do over, I would go with a 24″ raised heel truss, as this would offer not only significantly more R-value in this area (for relatively little expense), it would also make any inspection or repairs in this area much easier to deal with.

mbr w: rockwool in walls
Installing Rockwool batts in the walls of the Master Bedroom.

As each piece of Rockwool batt was installed, it was important to keep any butt joints between cut pieces tight together. Also, once each piece was snug inside the stud bay I finished by gently fluffing the outside perimeter edges so the Rockwool sat as flush as possible to the 2×6 studs, thus maximizing their R-value.

mbr rockwool complete
Master Bedroom ready for Intello on the walls before drywall gets installed.
family rm w: rockwool
Family room ready for Intello and then drywall.

Intello

With 4″ of Rockwool Comfortboard 80 on the exterior of our sheathing, the code specifies that we could’ve just used latex paint as our interior vapor retarder (Class III).

Again, to improve our margin for error, I felt like it was worth the added expense and time to install a smart vapor retarder (CertainTeed’s Membrain product would’ve been another alternative) to avoid potential issues with diffusion in the winter.

When I asked a question on GBA about this issue, the consensus seemed to be that the Intello, although technically unnecessary, was a nice bit of insurance.

It also added a final layer to all of the previous air sealing details. With redundant layers of air sealing, even if small areas experience failure over time, there are still other areas to back it up, thus maintaining our overall air tightness for the long term.

intello at frt dr basement
Intello installed in the basement stairwell by the front door.
finishing intello mbr
Intello in Master Bedroom nearly complete.

Sealing the Intello to the subfloor was one of the final air sealing chores of the build. It was deeply gratifying to finally get to this point, especially since drywall and then flooring were up next.

tescon on intello at subfloor
Intello taped to the subfloor with Tescon Vana tape.
intello tvana complete mbr
Intello complete in the Master Bedroom.

Thoughts on Advanced Framing Techniques

If I had it to do over, I would use less framing around windows and doors, along with using pocket headers instead of the more traditional insulated headers we ended up with. Pushing the header to the exterior sheathing would mean being able to insulate the pocket on the interior side with Rockwool or dense pack cellulose, rather than the rigid foam we ended up with (unfortunately, XPS in our case).

family rm w: rockwool
Family room ready for Intello.

Before we had to fire them, the two GC’s we were still working with as framing began were unfamiliar with advanced framing techniques, and they were already struggling to comprehend the many Passive House details in the drawings (not to mention many of the conventional details) so, as I’ve noted elsewhere, I had to pick my battles carefully.

Another change I would make would be at points where interior walls meet up with exterior walls. Rather than using ladder blocking to make the connection, which is still better than more traditional methods (creating a boxed in void that’s virtually impossible to insulate), I would utilize a metal plate at the top of the walls to make a solid connection. In addition to making drywall installation easier since it would create space between the two intersecting walls for sheets of drywall to be passed through, it would also make installing insulation, especially batt insulation, much more straightforward with clear and easy access (no horizontal blocking to get in the way).

intello at ladder
Intello at partition wall that meets the exterior wall (using ladder blocking).

A ProTradeCraft article discusses what builder David Joyce believes is ‘worth doing’ in terms of advanced framing techniques. Perhaps just as important, he points out what he believes can be safely ignored, or is just ‘not worth doing’ when it comes to OVE.

In this Matt Risinger video, architect Steve Baczek delves into some of the key components he uses to optimize advanced framing techniques:

In addition to the pocket headers, the idea of using header hangers instead of additional jack studs, seems to make a lot of sense.

And here’s a ProTradeCraft video regarding their own take on Advanced Framing:

One final change to our framing would be opting for 2-stud corners instead of the California 3-stud corners that we have. Although a relatively small change, I think a 2-stud corner is cleaner and allows for slightly more insulation in this vulnerable area.

Clearly each designer, architect, GC, or framing crew will have their own particular views on advanced framing, so there’s room to make individual choices without undermining the goal of balancing structural integrity with reduced energy demand. Local codes, along with the opinion of your rough framing inspector, will also have to be accounted for.

My guess is these techniques will continue to evolve, especially if specific products come to market to aid the process (i.e. reduce the amount of framing lumber required while ideally also lowering labor costs, all without negatively affecting the overall strength of the structure).

intello kitchen
Intello in the kitchen complete.

One final attempt at some additional air sealing was around outlet and switch boxes as they met up with the Intello. With a bead of HF Sealant, it was easy to make an airtight connection between the Intello and the box.

cu intello at outlet
Completing connections around outlet and switch boxes with HF Sealant.

At doors and windows, I finished these areas off with a strip of Tescon Vana tape, just as I had at the top and bottom of the walls.

intello complete br2
Completing Intello around a bedroom window.

Because corners tend to be problematic in terms of air leakage, I also added a dab of HF Sealant to these areas for the sake of some added redundancy.

lwr lft corn wdw w: intello & tape
Lower left corner of window with some added HF Sealant in the corner.
upper rgt corner wdw w: intello
Upper right corner of a window just before final piece of Tescon Vana tape is run across the top of the window frame, tying together the Intello and the light blue Profil tape that is air sealing around the window.

Sound Attenuation

Since we designed our home with a smaller than average footprint, incorporating many Not So Big House principles (roughly 1500 square feet for the main floor, with another 1500 square feet in the full basement below), one way to make the floorplan feel larger than it actually is was to provide some sound attenuation in key areas (we incorporated several other techniques to “expand” the feel of the floorplan that will be discussed in upcoming posts regarding interior design).

For instance, we installed the Rockwool in the long partition wall that runs east-west down the center of the floorplan. This wall helps define the barrier between public areas (kitchen and family room) on the south side of the home and the private areas (bathrooms and bedrooms) on the north side of the home.

We could’ve used Rockwool Safe ‘n’ Sound, but at the time, during construction in the fall of 2017, it was a special order item in my area, whereas the batts were already in stock, both for my main 2×6 partition wall, a 2×6 plumbing wall, and the remaining 2×4 walls that we felt could benefit from the Rockwool.

In the photo below, the Rockwool in the main east-west partition wall is covering the refrigerant and drain line for one of our three Mitsubishi heat pump heads, along with the usual electrical conduit for outlets and light switches.

rockwool 2nd br entry hall
Rockwool added to some interior walls for sound absorption, thus reducing unwanted sound transmission between certain spaces.

Here’s another view of this partition wall, this time from the opposite side inside the second bedroom:

rockwool 2nd br interior side
Same section of east-west partition wall from inside the second bedroom.

We also added Rockwool to the wall that connects the master bath to the 2nd bedroom bath, and between the 2nd bath and 2nd bedroom. The Rockwool was even added to the wall between our kitchen and utility room, where we have our washer and dryer, in the hopes that it would limit the amount of noise coming from the machines (which it thankfully has).

rockwool bath walls
Rockwool in bathroom wall around main waste stack.

Although this doesn’t make for a totally sound proof connection between spaces (we weren’t prepared to take things that far — roughly equivalent to air sealing a Passive House in the amount of detail required), the ability of the Rockwool to significantly muffle sound between rooms is quite impressive and, for us at least, well worth the effort and added expense.

rockwool kitch - utility
Rockwool in the wall between the kitchen and utility room.

For instance, while standing in the master bathroom, should someone be running water or flushing the toilet in the 2nd bathroom directly on the other side of the wall, the majority of the sound that reaches your ear comes by way of the master bedroom doorway, not through the wall directly. Out of curiosity I tested this idea with music playing on a portable stereo in the 2nd bathroom with the same results — sound through the wall is dramatically muffled, while the same sound that easily travels out of the bathroom and makes it way via the bedroom doorway is crystal clear. With the door to the 2nd bathroom and our master bedroom door closed, this same sound is obviously further reduced.

It’s also nice to watch TV in the family room and know that as long as the volume is at a reasonable level you’re not disturbing anyone trying to sleep or read in the two bedrooms. This kind of sound attenuation also adds a level of privacy to the bathrooms while they’re in use.

And, again, it’s not that no sound is transmitted from one room to another, rather it’s almost entirely limited to doorways, thus significantly reducing the overall impact of the noise that is transmitted. In other words, our goal was rather modest, we were just after significant sound absorption, not sound proofing (e.g. the level of noise cancellation required in a professional recording studio or a high-end home theater room).

As a result, I would definitely use Rockwool for sound absorption again. In fact, I can’t imagine going without this kind of sound attenuation (or something akin to it using other products or techniques outlined in the videos above) now that we’ve been able to enjoy it in our new home. It effectively prevents the issues often associated with so-called “paper thin” walls.

Arguably, addressing this issue of unwanted sound transmission is even more important in Passive Houses or high-performance homes that are already much quieter than conventional homes because of the extensive air sealing and well above code levels of insulation. In our own case, outside noises either disappear entirely or are significantly muffled — this includes a commuter train a couple of blocks away.

As a result, any noises within the home itself become much more pronounced since they don’t have to compete with the typical noises coming from outside the home. For instance, when we first moved in the fridge in the kitchen was easily the most obvious, consistent sound in the house. After a couple of weeks it just became background noise we’ve grown to ignore, but it was surprising just how loud it was initially, especially our first few nights in the home when everything else was so quiet.

In addition to excessive air leakage and obvious temperature swings between rooms, along with poorly sized or placed window layouts, the lack of any sound attenuation between rooms is one of the issues we notice the most when we’re inside more conventionally built homes. Much like all of the conveniences associated with a modern kitchen, it’s easy to take something like effective sound attenuation for granted until you’re required to go without it (e.g. in the case of kitchens while on a camping trip or waiting for a kitchen to be remodeled).

With all of the Rockwool batts in place, and the Intello installed over the exterior walls, drywall could finally go up.

Drywall

We went with USG 5/8″ EcoSmart drywall (GBA article on EcoSmart). We chose the 5/8″ over 1/2″ mainly for added durability and some slight sound deadening between rooms.

I had read about Certainteed’s AirRenew drywall, but it sounded like the only VOC it absorbed was formaldehyde, which, if I understand the issue correctly, can be safely avoided with the use of appropriate cabinets and furniture. If memory serves, AirRenew works by utilizing a compound similar to triclosan, meaning a biocide, which some believe can have potentially serious health effects. It’s not clear to me, even now, whether the use of AirRenew drywall makes sense, or exactly what compound (or series of compounds) are utilized to absorb the formaldehyde since Certainteed has remained silent on this point, claiming the information is proprietary. Nevertheless, it has a Declare label, so ILFI must believe it’s reasonably safe to have on painted ceilings and walls.

At any rate, we wouldn’t be bringing in any new furniture that would have elevated levels of VOC’s (including flame retardants) once construction was complete. Since our last house was significantly larger, roughly 2,800 sq. ft., it was fairly easy to downsize, donating or giving away what we couldn’t use in our new house, while holding on to our favorite and most useful pieces. It also helped that we never really filled up our last house (e.g. we never got around to purchasing a formal dining room set), so we didn’t have as much “stuff” to discard as we might have.

Moreover, by being mindful of every finish we create or use (primers, paints, wood flooring, grout sealer, caulks and sealants, kitchen cabinets etc.), along with any other products we might bring into the new house (e.g. surface cleaners, new furniture, fabrics, even perfumes and colognes, etc.), we’re hoping to maintain a high level of IAQ.

The International Living Future Institutes’s Red List and their database of Declare products were a big help to us, even though we’re not pursuing any kind of certification with them. The Greenguard certified label was also helpful, in particular when it came time to choose tile and grout.

By consciously choosing every product and material that comes into the home, it’s possible to at least reduce our exposure to harmful VOC’s and chemicals. While still imperfect (Who can you trust?), these kinds of programs do allow designers and homeowners to take some control over the environments they’re creating and living in, which is empowering to a degree. Far better if the US regulatory bodies operated under a precautionary principle model when it came to industrial products.

Frankly, in a rational system, one that was truly looking out for the best interests of consumers, this kind of research — time consuming and frustrating busy work to put a finer point on it — would be considered laughable if not horrifying. In a rational system it would be safe to assume that any product for sale, apart from some careful instructions on their use and disposal, would be safe to have inside your home without having to worry about short or long term health implications.

Nevertheless, if unintended health consequences are to be avoided during a renovation or a new construction build, consumers have little choice but to do the necessary homework (or pay someone else to do it for them) and be as thoughtful as possible with their selection of materials.

drywall family rm
Kitchen and family room after drywall was installed. Ready for primer, paint, and flooring.

Now that all of the elements of our wall assembly were complete, it was time to have some fun with final finishes: flooring, wall colors, wood trim, doors, kitchen cabinets…

 

Siding Part 2: Charred Cedar (Shou Sugi Ban) with Natural Accents

2

Building a Passive House: Science, then Art

We wanted the process of creating our new home to be fun, so from the outset we approached the build as a mix of science experiment and art project.

For the structure, this meant utilizing building science research to properly air seal, insulate, and ventilate to ensure that we ended up with a house that’s hopefully durable, stingy with its use of electricity, and that functions well on a daily basis for many years to come.

In terms of design, it meant spending an inordinate amount of time on the floor plan, carefully defining how we would move through and live in the structure, while also carefully considering the seemingly infinite options when it comes to finishes, both for the interior and the exterior of the home (with an emphasis on low or no VOC products to protect indoor air quality) .

With most of the wall assembly details finally in place on the house, putting up the charred cedar siding represented the first real transition from science to art. And with Passive House details mostly taken care of, we could begin to make decisions in real time regarding how we wanted the house to look, both inside and out, in terms of finishes.

Since our house is relatively small, at least by recent American standards, many of the sins associated with McMansions were easy to avoid (McMansion Hell faces lawsuit).

On a side note, if trends continue, owners of these McMansions may be in for a rude awakening when it comes time to sell:

South Barrington McMansions Languishing
McMansions at Fire-Sale Prices

Affluent Chicago suburbs aren’t alone in facing this dilemma:

McMansions No One Wants
Killing the McMansion

If such reports prove to be accurate, and tastes really are fundamentally changing, perhaps it can be tied to a growing awareness of climate change and its implications. After all, these larger homes tend to be energy hogs, not to mention maintenance nightmares because of poorly planned and executed construction details — in part, a consequence of preferring quantity over quality. Moreover, there’s a growing chorus of voices espousing the benefits of simplicity (e.g. the tiny house movement, or minimalism). This is often wedded to an appreciation for the handmade or artisan object, as opposed to the mass-produced, and typically homogenous, product.

Nevertheless, it seems doubtful that the suburbs will ever be abandoned wholesale, and for any number of reasons.

For more on suburbia, go here: Building in the Suburbs

Massing: Basic Forms

For our house, the structure is a basic rectangular box with a gable roof (long sides face north and south with the gable ends to the east and west). It’s not unlike the basic form most children would come up with if prompted to draw a house. We really like the simplicity of this kind of roof style for aesthetic reasons, but also for the ease of installation and the long-term durability of the roof.

When we concentrate on the essential elements in design, when we omit all superfluous elements, we find forms become: quiet, comfortable, understandable and, most importantly, long-lasting.
—Dieter Rams

Bronwyn Barry has even coined a hashtag for this use of very basic forms,  #BoxyButBeautifulespecially popular with Passive House design since it can help eliminate potential thermal bridges while making air sealing more straightforward.

1st layer rockwool at frt door
Wojtek installing Rockwool around the front door, next to the garage.

We tried to avoid having the garage as part of the front of the house, in particular having the garage door facing the street (a look I’m not fond of), but physical limitations, in terms of the lot itself, left us with little choice in the matter. So rather than repeat the gable roofline of the house, we went with a shed roof for the garage. The shed roof adds some visual interest, while it also ensures that any rainfall in this area immediately gets sent to the north side of the house where we want it — away from the foundation as well as bypassing the driveway altogether (water flows to the north on our street).

We also felt that these two rooflines fit in well with our Urban Rustic design aesthetic. As a mash-up between early 20th century city and farm, both the simple gable and stark shed rooflines would be equally at home in an agricultural setting or on a densely packed inner city block.

In addition, it was important to us to have some fun with color, so on the exterior using black charred cedar with some natural highlights would give us the bold look we were going for, while accent walls inside with bright, playful colors would help bring the interior to life, accompanied by hand-made or hand-selected decorative objects in various bold colors.

When done well, this child-like use of color can lend a space or structure a real sense of vibrant energy.

Already a fan of Jack White’s use of color for album artwork and the staging of live shows for The White Stripes, I appreciated the way he chose to decorate the exterior of his Third Man Records in Nashville. A form that was as basic as it gets — single story brick warehouse — becomes vivid and hard to miss, in a good way, with a splash of color on what would otherwise be a monochromatic black box. The “insert” around the front door, offering a little shelter with some nice shadow lines, along with the crisp signage finish off what is a clean, sleek, but still playful, look.

3rdmanrecords
Facade of Third Man Records in Nashville.

He’s done something similar with the interiors, in this case for the Detroit store:

Siding Layout for our Charred Cedar (Shou Sugi Ban)

Since we were building custom, rather than working within the constraints of tract housing in a larger subdivision (as we did with our first house) where many of the design choices are already made for you, we knew we wanted to take some chances in terms of materials and layout.

It also helps that we’re in a neighborhood with mixed architectural styles, including single-family homes and townhomes, with structures and exteriors running the gamut between old and new, as well as traditional and contemporary. We felt like this gave us more latitude to try something different without upsetting the overall look of the neighborhood.

With a smaller structure and only two basic rooflines, we knew any experimentation or design risk was going to have to occur at the level of siding materials and their orientation.

Knowing its weaknesses, I never imagined using wood for any part of the exterior of my house should the day come when I could build my own home. Brick, stone, metal, any number of man-made products (e.g. PVC or Boral), all seemed like the smarter way to go to avoid maintenance headaches and costly repairs. I assumed we’d end up using Hardie plank siding, or one of their paneling configurations, or maybe even some kind of metal product.

But then I came across charred cedar, or shou sugi ban.

It’s hard to remember now exactly where I saw it for the first time since it would’ve been before 2015 probably, but I think it was a Dwell magazine profile of Terunobu Fujimori’s work. I may have even first seen the same architect featured in Philip Jodidio’s book Architecture Now! (HOUSES, volume 1). Regardless, once seen, it was hard to forget.

When we first began working with our initial builder, Evolutionary Home Builders, I brought them some rudimentary drawings I had done, expressing our desire to try something creative and out of the ordinary, especially in terms of siding layout.

sketch black:gray
An early drawing of mine showing mostly gray with black accents for siding.

Instead, their architect, Patrick Danaher, came back with an extremely conservative layout, one that’s fairly omnipresent when looking at single story ranch homes in the Chicago area.

ehb s and w elevations
Proposed siding layout from Evolutionary Home Builders.

Our use of charred cedar would have been the one change from what is typically a combination of brick or stone on the bottom 2/3 of a wall with painted or stained wood up above, usually with a limestone ledge in-between to visually and physically separate the two materials.

brown - brick typical layout
Popular way to break up the cladding on a ranch home, in this case mixing brick and wood.
brick w: light sd
Another example of the same layout, this time with lighter colored siding.

The photos above are included not to disparage this look, which I actually like, but to give specific examples from our area of this traditional layout; one that’s seen on probably thousands of homes in just the Chicago area alone. Although attractive, I couldn’t help but feel that this layout was a cliched repeat of what’s already been done countless times before, which, nevertheless, would’ve been entirely appropriate had we been asking for a more traditional look.

Instead, it was pretty shocking to get their initial drawings since I had clearly expressed our willingness to think outside the box in order to experiment with something unique and fun, even avant-garde (or, at the very least, contemporary). The fact that Brandon Weiss (the owner) and Eric Barton (chief field officer) were also in these design meetings and they, too, had nothing to offer on this point did not seem to bode well for our project.

Initially I lacked the confidence to argue against Patrick’s suggested layout (they’re supposed to be the experts, right?). I just assumed my ideas were simply too bizarre to work. Over time, particularly as I saw how they did things with a lack of care and a lack of attention to detail (see below), combined with looking around online and seeing how other projects experimented with unique siding layouts, I eventually realized there was no reason not to try something bolder and more well thought-out.

In the meantime, I put together a fairly large sample board, mixing the charred cedar with the natural cedar mostly in accordance with their initial suggested layout:

charred cedar sample board with natural
Sample board with natural and charred cedar.

This sample board, although attractive, confirmed a couple of things I was worried about:

First, the layout was way too traditional looking, even with the charred cedar.

Second, this amount of natural cedar around the house would be a pain to maintain over the years, costing me significant time and energy, if not money (the maintenance labor would be DIY), probably requiring a fresh coat of tung oil at least every other year, if not annually. Since we wanted a natural look, any kind of traditional spar varnish, or other shiny clear-coat, didn’t seem appropriate. Although one option, open to us even now, is to just let the tung oil break down and let the natural boards turn gray over time (although it can be a somewhat unpredictable process).

Finally, since we felt the charred wood next to the natural was visually so electric, I thought it best to limit the combination to try and heighten the effect.

natural-and-charred-together
“Natural” cedar, treated with tung oil, next to the charred cedar.

In the end, Patrick’s suggested layout struck me as rather staid and uninspired (if not, to put it bluntly, half-assed).

On a side note, we didn’t have much luck with the three or four architects we came across during our build. They seemed mostly disinterested when they weren’t outright lazy. See the floating toilet in our initial drawings:

floating toilet
First look at our initial drawings from Evolutionary Home Builders — note the floating toilet in the middle of the basement floor.

No one — not the architect of record, not Patrick, not even Brandon the owner — could be bothered to give the drawings even a cursory edit/revision before handing them over to us. This certainly planted the seed, along with their generally disordered style of communication, that all was not well regarding the level of care, or even interest, our project was going to receive from them for the duration of the build.

I guess the situation could’ve been even worse:

Unfortunately, the issues we had in establishing our siding layout were emblematic of our overall experience building a new house, whether it was with architects, general contractors, or some (but certainly not all) of our subcontractors: we were shocked by the overall lack of integrity, curiosity, and workmanship.

Far too often it felt like rather than having partners in an exciting process we were actually being held back by people who didn’t seem to really enjoy what they did for a living. Making matters still worse, not only did they seem bored, but the work itself was often mediocre when it wasn’t clearly incompetent.

Unfortunately, even acting as our own GC didn’t help matters, since a competent GC with a long track record has had the time to develop relationships with subcontractors he or she can trust to deliver in terms of schedule and craftsmanship.

I keep coming back to these issues in multiple blog posts mainly as a warning to others who are considering pursuing their own self-build (or even hiring a general contractor to do the work for them), encouraging them to have realistic expectations and to better understand just what they’re up against when it comes to the construction industry — particularly if they wish to try anything new or different.

At any rate, with the decision made to use the charred cedar, we went ahead and prepped the wood before construction began. You can read about the details here:

Cedar Siding Delivered…
Oiling Charred Cedar Siding

Installing the Charred Cedar

With all of the components of our wall assembly in place, Wojtek and Mark finally started installing the charred cedar on the house, beginning with the garage. This was easily one of the most exciting moments of the build.

I think Wojtek and Mark were secretly excited, too, if only because they were finally finished with all of the insulation and layers of strapping.

1st pce char going on
Wojtek and Mark installing the first piece of charred cedar on the south side of the garage.
1st few rows south sd sd gar
Wojtek and Mark making progress on the south side of the garage.

It was more than a little exciting to see the first pieces going up, especially considering how far off-track our project had gotten early on.

s garage char 1:2 way
First few rows of charred cedar going up on the south side of the garage.

With no choice but to have the garage thrust forward and so prominent on our front elevation, we just had to make the best of the situation. One way of addressing it was to shake up the orientation of the charred cedar. Since the house itself was going to be all vertical (we just find it more interesting), it made sense to change the north and south sides of the garage to horizontal.

south garage 1st pce east wojtek and mark
Wojtek and Mark starting the east, vertically oriented, side of the garage.

In doing so, on the south side by the front porch this horizontal orientation would draw in the viewer’s attention, hopefully pointing it towards the front door of the house. Even as you walk up the front steps this horizontal orientation, I would argue, does its subtle magic fairly well. At the street, or out in the front yard, this effect seems to work even better.

garage south sd start east wojtek and mark
Finally getting to see the combination of horizontal and vertical orientations combined.

In mixing the siding’s orientation in this way it also helps to show what the material can do visually. Lastly, having these two sides of the garage oriented horizontally should also emphasize that this portion of the structure serves a different function (i.e. garage vs. house).

After having the charred cedar hidden away in storage for so long, it was extremely rewarding to finally see it going up.

close up char on garage texture
Close-up of several charred cedar boards.

It was nice to see that it was every bit as beautiful and interesting to look at as we had initially thought while making it.

oil and texture on garage sd
The range of textures and subtle variation in color makes the charred cedar truly unique.

In keeping with our Urban Rustic aesthetic, the charred cedar — which would look just as good on a farmhouse or outbuilding as it would on an early 20th century artisan workshop or small factory warehouse — also represents our desire to bring in elements that reflect the Japanese notion of wabi-sabi.

For example, stressing the wood with fire instantly gives it an aged appearance, and the amount of variation also makes clear it’s a natural material, as opposed to an industrial product manufactured to meet narrow and precise tolerances, with the goal being absolute uniformity. Whether it’s the knots, the lighter or heavier areas of char, some areas of natural cedar peeking through, or the ‘oil stain’ marks, the charred cedar emphasizes and celebrates imperfections and inconsistencies in the wood, sometimes to great effect even within a single piece — to the point where the most singular board catches your eye and you can’t help but linger over it. Instead of being annoyed by difference, the charred cedar actually encourages you to go looking for the most unique boards.

Following installation guidelines, Wojtek and Mark used only stainless steel nails to attach all of the cedar siding.

garage sd out front door
View of the garage from the front doorway.
south gar sd mostly done mark in bg
First look at a large section of the charred cedar siding installed.
south gar sd bringing you in to frt dr
A second view.

With the south side of the garage mostly complete, Wojtek and Mark could move on to the north side.

n side garage furring and coravent
North side of the garage prepped and ready for siding.
1st pce north gar sd
First few pieces going up on the north side of the garage.

For the soffits, we were initially going to use another Cor-A-Vent product, their PS-400 Strip Vent to complete our ‘cold’ roof assemblies, which on the house already included a ridge vent.

Cor-A-Vent PS-400 Box
Box of PS-400 strips for soffit ventilation.

But after opening the box and really taking a look at the product, they just seemed really flimsy. I’m sure they work fine, but holding them in your hand doesn’t exactly breed confidence. Also, seeing Wojtek’s stink face as he carefully studied a couple of pieces only confirmed that we needed another option.

After looking around online, I ended up finding a product at a local Home Depot — Kwikmesh, a galvanized all-purpose metal mesh on a roll.

mesh for soffits
Metal mesh product we used for soffit ventilation.

Not only did the Kwikmesh appear more substantial, I thought it would look better with the charred cedar than the PS-400, making for a nice contrast with the wood. I also really liked how it revealed some of the structure through the mesh for a more raw, unfinished look — again, in keeping with our Urban Rustic design goals.

close up soffit screen complete
Close-up of the soffit metal mesh installed.
outside view n gar soffit
First section of soffit going up with the metal mesh in place for ventilating the roof.
mark w: gar soffit screen mostly complete
Mark waiting for a cut, with most of the soffit and siding installed on the north side of the garage.
garage soffit w: screen complete
Section of soffit complete with Kwikmesh installed.
north garage sd soffit complete
North side complete, with the frieze board finishing off the rainscreen details.

We were going to copy a Hammer and Hand diagram for the top of a wall, in particular their rainscreen detail for the frieze board:

https:::hammerandhand.com:best-practices:manual:4-rain-screens:4-1-top-wall:
Courtesy of Hammer and Hand and their Best Practices Manual.

After talking through the details, Wojtek and Mark found the notch in the frieze board to be an overly fussy detail, preferring to keep this piece fully intact. To do this, they ripped down 2×2 furring strips to a thickness they could use as blocking behind the frieze board, pushing the frieze board out just beyond the plane of the siding, leaving a roughly 1/4″ continuous gap.

Apart from slightly more room directly above the Cor-A-Vent strip, the end result is much the same — a small gap between the frieze board and the top piece of tongue and groove siding allows air behind the siding to flow freely up and out of the wall assembly through the top of the Cor-A-Vent strips.

The Cor-A-Vent strips are kept about a 1/4″ below the initial blocking directly above them.

wd view top of garage rscreen
Top of the wall is ready for siding, and for establishing the air gap for the rainscreen.
mark blocking 4 frieze and vent
Mark adding blocking in preparation for the frieze board to finish off the top of the wall.

A close-up view from the side showing the details for the rainscreen at the top of the wall:

wide view garage frieze w: blocking sd
Top of the Cor-A-Vent and the top piece of siding. Frieze board being installed over blocking in the background.

On the house, the guys adjusted the placement of the frieze blocking, lowering it so that it was in line with the first layer of 2×4 blocking, thus closing off any unnecessary open space behind the frieze board.

close up rainscreen gap n garage
Close-up of the soffit with frieze board and air gap for the rainscreen directly below it.

With the north and south sides of the garage mostly complete, the guys moved on to the front of the garage.

garage south sd start east wojtek and mark
Wojtek and Mark moving across the front of the garage with the charred cedar now oriented vertically.

The change to our wall assembly — using 2×4’s instead of 1×4’s for our first layer of strapping so that the siding could hang down just past the metal flashing and Rockwool on the foundation — had one nasty unintended consequence for the north side of the house: the 14′ boards we had purchased, charred, and oiled were now about 3″ too short — they were initially supposed to sit just above the flashing and Rockwool, not hang down several inches below this area.

With little time to spare, since Wojtek and Mark were cruising right along, my wife Anita and our friend Maria worked tirelessly to get longer boards completed in time, while I tung oiled each board almost as soon as it was burned.

char as garage sd east goes up
Anita starting to burn additional boards as Mark and Wojtek keep working.
most of east side garage complete
Mark mostly done with the front of the garage.

For the front of the garage, Wojtek and Mark repeated the same rainscreen details, only this time with the siding oriented vertically.

sd soffit w: frieze for vent gap
Overhang on the front of the garage: frieze board completing the rainscreen, soffit boards, and rake boards being installed.
garage soffit and rake
Closer view of garage soffit and rake being installed.
garage side view strapping vent sd
Cut away view of the siding with a rainscreen set-up behind it.

Wojtek and Mark did a nice job with the soffits at all of the outside corners.

Note the ‘tiger striping’ on the bottom edge of the rake fascia board, along with the variation in color and texture from one board to another — an example of ‘perfectly imperfect’ according to wabi-sabi principles — including the subtle pencil marks for their cuts (still visible almost two years later).

outside corner soffit w: tiger stripe
Close-up of the garage soffit at an outside corner.
nw corner garage start n sd
The guys making the transition from the garage to the north side of the house.

For the north side of the house I wanted to keep the charred cedar a monolithic black. The only real relief from this was the change in orientation of the siding from the north side of the garage to the house, along with a single window for my daughter’s bedroom.

north side char
Charred cedar on the north side of the garage and the house.

Knowing that the other three sides of the house would be getting some natural cedar accents, I thought keeping at least one side of the house entirely black would make for a nice overall effect.

mark at mechanicals
Mark working around the mechanicals on the north side.

The Pittsburgh Steelers did something similar, having their team logo on only one side of their helmets, leaving the opposite side a solid black. I always thought this was visually striking.

Installing the Natural Cedar Accents

The west side of the house would be the first opportunity to use some of the natural accents. Based on my initial drawings and the sample board, I wanted to limit the natural as much as possible while still allowing it to have a strong visual punch.

stacks of nat'l and char in garage
Natural cedar boards tung oiled and ready to be installed.

I wanted to take advantage of the drop-off in grade that’s present in the backyard by using the natural boards around the window on the left. In doing so, it would draw attention to the change in grade, emphasizing that the left side of the west facade is significantly taller than the right side.

Using the structure of the window itself as a guide would help me to decide exactly how many natural boards to use.

west 1st cple pcs nat'l wojtek and mark

In addition, I knew I wanted a more informal look, making it consistent with our Urban Rustic and wabi-sabi design goals, so using an odd number of boards in an asymmetrical way would help achieve this.

west after 1st few nat'l pces
Adding natural boards around the window on the west facade.

By focusing on the window in this way, 11 natural boards turned out to be the right number. Looking closely at the way the window itself is framed (large center piece of glass surrounded by two smaller pieces), if we had gone with fewer boards the natural would be too far away from the dead center of the window opening, so insufficiently ‘wrapping around’ the window, while any additional natural boards risked being too close to dead center, making the overall look too symmetrical.

Obviously, a lot of the details regarding these decisions are subjective, but having some kind of framework for a final decision is nice to have, rather than going strictly on instinct alone.

mark just past nat'l on west
Mark completing the natural accent around the left window.

It was only after Mark went back to the black charred siding that I was sure we had exactly the right amount of natural boards around the window.

mark and wojtek west sd after nat'l
Mark approaching the center of the west facade.

By going just past the first piece of glass, the natural boards have a nice asymmetrical look to them — hugging or slightly wrapping around the window just enough, making a connection, but not too much.

After so many months of planning, worrying, and waiting — and then finally getting to see this combination of charred cedar with the natural cedar — watching the siding go up was easily one of the most gratifying parts of the entire build.

wojtek burning cut edge
Wojtek and Mark were nice enough to take the time to char all the cut edges.

When the guys got to the middle of the west facade they were in for a nice surprise — dead center of the peak lined up perfectly with the seam between two boards.

lking up sd at west peak
Looking up at the center of the west facade.
lking up sd at west peak wider view
Wider view of the peak on the west facade.

On most houses the back side tends to be rather boring, as if it were mostly forgotten about (at least in visual terms). In part this is no doubt because the details used to create visual interest are normally reserved for the front elevation where they can show off to the street. Where the front might be covered with stone accents, metalwork, elaborate lighting fixtures, or some other decorative accents, the other three sides tend to blend together as the basic siding material just continues its standard layout or pattern around the perimeter of the house. These decorative accents add cost to a build, so it makes some sense to reserve them for the side of the house that most people will see.

west facade sd after peak

Sometimes, however, this effect can be jarring. In a Chicago suburb there’s a house that uses elaborate stonework on the front facade, which in this particular case is actually two sides that face the street, but when you walk around to the back of the home the siding material transitions to wood. Because the transition is so abrupt, and the quality of the materials is so different, in terms of both cost and visual impact, it almost feels like walking behind the elaborate facade of a building on a movie set to discover it’s only a single wall propped up to mimic a much more substantial building. This lack of cohesiveness lends a kind of sadness to the house, as if it announces that the elaborate plans for the exterior cladding were ruined by unexpected budget constraints.

west sd mostly done guys start south

Consequently, we felt it was important to give each side of the house its own distinctive face. Because of the size and layout of our lot, and the way the houses next to us are positioned, it’s difficult to view more than one side of our home at any one time, which only encouraged us to make this a priority.

west facade after sd b4 gutters
West facade mostly complete.

Quick side note: these windows on the west facade are the ones with Suntuitive glass. Because of this, we’ve never required any blinds or any protection from glaring afternoon sun. As a result, we’ve been able to enjoy a constant, unimpeded view of the backyard.

More than a year after the siding had been up my daughter and I were in the backyard doing some gardening when she pointed out that the back of the house looks like David Bowie’s Aladdin Sane makeup. We have a magnet of Bowie on our kitchen fridge. She has a point.

It’s not difficult to see a face in the facade, and the music reference fits in nicely with our rock ‘n roll theme for the interior of the house.

The effect of the natural cedar is also reminiscent of racing stripes, especially those seen on sports cars or muscle cars, or even motorcycles (e.g. the graphics on racing sportbikes). This was partly done with tongue planted firmly in cheek — if high-performance cars and motorcycles look good with racing stripes why not on a high-performance home? — but mainly because I’ve always enjoyed the visual power of these types of graphics.

sd west b4 gutters
Waiting for gutters and downspouts.

Also in keeping with the racing stripes idea, we wanted the house to look distinctive on every side, much like the well-designed shape of the most memorable sports cars or motorcycles that look good from almost any angle.

At the beginning of each episode of Comedians in Cars Getting Coffee Jerry Seinfeld does a great job introducing each vehicle, explaining why some of them — even if decades old and built with what we consider now to be obsolete technology — can still elicit such intense feelings of affection or outright joy.

And there’s no shortage of design options when it comes to racing stripes and their various layouts.

Many are symmetrical, for instance, a double stripe laid down in thick pairs with little space between. This style is popular on the hoods of muscle cars.

Shelby stripes
Shelby Mustang. This one is more elaborate with the added red stripes along the outside edges.

Sometimes the striping is fairly subtle, arguably more of a pinstripe effect:

And of course the racing stripes don’t always have to impart a sense of speed or domination, sometimes they’re a nod to smart, even cute, styling.

Motorcycle graphics are probably the most extreme version of racing stripes, many of them even outlandish, but mostly in a vibrant, fun way.

Ducatis look great when they’re fitted out in monochromatic red, or even all matte black, but white stripes definitely add another dimension to the overall look of the bike:

This is one of the more iconic layouts, from Honda’s factory MotoGP racing team, Repsol.

repsol full

I think the layout and color combination looks even better in close-up as a screensaver:

repsol screen saver
Vivid screensaver.

My favorite racing stripe layout is a combination of one thick and one thin, probably because of the asymmetry since it’s typically applied off to one side, or offset, rather than applied directly down the center.

love bug
“Herbie” for sale in an antique shop in Cincinnati.

Another example of this thick-thin combination:

racing strip hash marks wheel
Hash marks on the wheel of a Dodge Charger.

The other nice thing about the racing stripe idea was that, as a visual motif, we could carry it over into some of the interior finishes. This is something we intended to do with the charred cedar as well — using an element from the exterior to decorate a part of the interior.

The blue-green-white combination, long associated with Kawasaki, would prove to be the most overt example where we would borrow some famous imagery from motorcycle racing and apply it inside the house in a new context, but for much the same reason, namely trying to impart a sense of playful energy and added brightness (more on this in a future post).

At any rate, I really enjoyed coming up with a kind of narrative for the look of the house, hopefully showcasing, in a unique way, what the charred cedar and the natural boards can do visually as siding on a home.

For the south side, we decided to use the kitchen door as our guide for putting up the natural cedar, while the front door would be used on the east-facing facade.

Another element around the two doors to consider was exterior lighting. A single fixture at each door would project an upward and downward concentrated beam of light, highlighting the natural boards in the dark as they pinpoint their focus on this band of natural wood surrounded by total blackness.

mark ready for natl at kitch
Mark almost ready for the natural cedar boards.

We started the natural boards to the right of center of the door’s glass, cheating a bit so that they started pretty much directly above the door handle.

1st couple at kitch

It also worked out nicely that the natural boards ended up in an A-B-A pattern from back of the house to front; meaning to the left of the window in back, to the right of the kitchen door, and then to the left of the front door.

mark past natl at kitch
Mark and Wojtek moving past the natural cedar boards.

We ended up at 5 boards for this side of the house, allowing the striping to stay proportional to the size of the opening while sitting just beyond the eventual light fixture. It also helps that the kitchen door, made up largely of glass and a neutral gray color, doesn’t take any attention away from the natural boards.

kitch dr
Kitchen door with its charred and natural cedar.

At the front door, I initially pictured the natural boards installed on the right side of the entryway. In two dimensional drawings this seemed to make sense, but after seeing everything in place in reality, it became pretty clear that to the left of the front door would be far better. To the right of the front door would’ve meant the natural boards would look ‘squeezed’.

1st pce nat'l at frt dr
Putting up the first piece of natural cedar around the front door.
mark finishing up nat'l at frt dr
Mark nailing in the first couple of natural boards.

Starting the natural boards just outside where the light fixture will sit, we ended up at 7 total boards for around the front door. Since the front door is slightly larger than the kitchen door, and it’s the main focus of the house, it made sense to have slightly more natural boards in this area.

Many thanks to Wojtek and Mark for their patience in playing along as I figured out exactly how many natural boards to use, and exactly where they should be positioned.

mark just after nat'l at frt dr

As each section of natural boards went up, it was evident that beyond a certain point the racing stripe effect would be lost: one too many boards and it wouldn’t look right, in effect, overpowering the opening; too few boards would mean not enough impact — less like a proper decorative accent and more like a disconnected mistake.

sd done b4 frt dr
First look at the east facade fully sided. Our little black box almost complete.

Bob Riggs, his son Brian, and Jason were nice enough to come back to install my front door for me. We used the Hannoband expanding foam tape to seal around this door, just as we did for all of the other windows and the kitchen door.

Check out the details of their installation here:

Windows, Doors, and Suntuitive
Brian Jason Bob install front door
Brian, Jason, and Bob install our front door.
frt dr frt yard
Front door just after installation.

The front porch with its charred cedar, natural cedar, and the bright red door reminds me of Coco Chanel’s famous “little black dress ensemble” — the charred cedar the little black dress, the natural boards the string of pearls, and the front door the splash of red lipstick.

Our shiny front door is the one sleek, clean, and clearly new element of our exterior. This contrast between industrially produced, sharp looking object and the burnt and heavily knotted wood in some ways personifies the Urban Rustic aesthetic.

frt dr clup b4 trim
Close-up of the front porch just after the door was installed.

Installing Sill Pans

When most of the siding and overhangs were complete, Wojtek and Mark started installing the metal sill pans for all the windows and doors.

Greg, the owner of Siding and Windows Group, suggested we use Lakefront Supply for all the flashings, which turned out well as they were able to create exactly what we needed.

sill pan inside edge b4 return trim 2nd view
Metal sill pan slid under bottom aluminum edge of the window.

In the photo below you can see the horizontal layer of 1×4 strapping, which becomes a nailing surface for the 1×6 cedar board that will be used as a return back to the window frame.

inside corner sill pan b4 return trim
A second view of the same area.
mbr wdw w: sill pan b4 final pce trim
From inside looking down at the sill pan.
side view sill pan edge beyond sd
Outside edge of the sill pan.
south wdw after sd b4 trim
Window waiting for the last few pieces of trim.

We were going for a “frameless” look for the windows so that once all the trim was installed very little of the window frame is left exposed.

k wdw trimmed out fmly rm wdw bg
Kitchen window with all the trim pieces installed.
innie wdw face - frameless look
Once the screens were installed, there was almost no room to spare. We really like this “frameless” look combined with the “innie” window position — it creates some really nice shadows at various times during the day.
frt dr sill pan
Front door sill pan installed.
kitch dr sill pan
Kitchen door with the sill pan installed.
Wojtek installing first sill pan
Wojtek pulling off the protective plastic on the sill pan.
mark and wojtek install 1st pce garage roof flashing
Mark and Wojtek installing flashing on the top of our garage roof.
2nd shed rf flash
Wojtek screwing down the flashing.

All of the elements finally in place: master bedroom window with natural accent, charred cedar used to return the siding back to the frame of the window, with the metal sill pan underneath.

mbr wdw frame sill pan

Gutters and Downspouts

For the gutters and downspouts we went with Nordic Steel. They’re expensive, but they’ve lived up to the marketing claims: with a larger half-round gutter and wide diameter downspout, we’ve never had to clean out our gutters (so far, anyway). They also look really nice, and they fit in well with the Urban Rustic feel we’re going for.

nordic ne
nordic n

Decorative Details

It was exciting to finally get the small, decorative pieces for the exterior out of storage. For example, I purchased our metal house numbers and our front doorbell on Etsy, at Modish Metal Art. As it turned out, Etsy proved to be an invaluable resource, both for decorating the exterior and the interior of our house (more on this later).

Our exterior lights were found on Amazon: Hyperikon

house numbers out of storage
‘Wobbly’ house numbers.
doorbell
Gecko doorbell finally installed.
house # and drbell
Front door details complete: trim, sill pan, doorbell, house numbers, and exterior light.

I found these white porcelain numbers on Etsy — made in Japan, so they seemed perfect for our shou sugi ban. Unfortunately, this Etsy shop is no longer in business.

With some Spax screws, and the charred cedar as a background, the white numbers really pop:

708 white porcelain w: spax

Stucco for Inside Window Wells

For inside our basement window wells we initially thought we would just carry the wood siding all the way down. Once the retaining walls were in, and we saw how complicated the cuts would need to be around the stone — not to mention all the work required in hammer drilling concrete bolts into the foundation to establish strapping for the charred cedar — we realized wood wasn’t really a viable option.

After contacting Rockwool directly, they told me stucco over the exposed Comfortboard 80 would work fine, although it wasn’t presented as an option in the paperwork they had originally given to me. This was a great relief, and Wojtek had a friend who installed stucco, so it ended up working out really well.

The window bucks around the basement windows took a real beating during the prolonged construction process, so I touched up the sills with Prosoco’s Fast Flash to make sure they were watertight.

Tomasz
Tomasz installing the lathe with long concrete screws in preparation for our traditional 3-coat stucco.

Tomasz would eventually take the stucco up to the Cor-A-Vent insect screen, and then Wojtek and Mark would lower the charred cedar below this point by several inches, completely hiding the seam between the two materials.

stucco 2nd coat k dr
Charred siding, corner of the window well, and the stucco (only 2 coats at this point) meet.

For the railings around the window wells we wanted to use a hog wire panel (in keeping with the Urban Rustic theme). Initially, I thought I would use Wild Hog Railing combined with wooden posts, but decided an all-metal railing system would be better, mainly for durability reasons.

wdw wll 3
Gutters going up just after the railings around the window wells were installed.
wdw wll 2
View of the railing from a basement window.

How Durable is the Charred Cedar?

Initially at least, our luck hasn’t been great with the charred cedar.

For instance, during our first summer with the siding last year we noticed that we had some carpenter bees buzzing around the house. At first, I didn’t think much of it since the charred cedar is supposed to be insect-resistant. But then I noticed a bee digging a hole above one of the windows and realized something needed to be done.

After reading up on their lifecycle, I used a spray inside the holes that were present (about 10 total after I went looking), following up a couple of days later with a few puffs of diatomaceous earth. After waiting two more days, I then stuffed each hole with some steel wool before covering each entry point with some black sealant. Once patched, these areas are virtually invisible.

This spring and summer we kept a careful eye on these specific areas, along with the house more generally, but no bees emerged, so it looks like the problem has been resolved. Nevertheless, it’s something we’ll need to look for every May and early June.

Looking back, the bees nested in the exposed sub-fascia on two sides of the house before the siding and overhangs were installed. At the time, not understanding their lifecycle, I just plugged these holes with some caulk, thinking that would suffice. Unfortunately, it wasn’t, and their offspring emerged the following spring/early summer digging through the charred cedar fascia. If I had properly addressed these spots with a spray and then diatomaceous earth combination initially, there’s a good chance I could’ve avoided this problem altogether.

Since their offspring return to the area where they initially emerged to create their own nest sites (or even to reuse the existing one), it’s extremely important to address the problem as soon as possible, otherwise one or two small nests can quickly expand to dozens of bees swarming around the eaves of a home in early summer. And, even more sinister, it’s these nesting tunnels that attract the attention of woodpeckers who go looking for them, hammering the wood to get to the larvae below the surface, and scarring, if not ruining, the wood in the process.

In fact, this past January there was a morning where I heard a sound like a machine breaking down, almost like a chain breaking off its wheel. When the sound moved across to the other side of the house I suddenly realized it was a woodpecker. Luckily, he was sitting on a downspout right outside our window, so just opening the window was enough to startle him and make him fly off. When I went outside to look for damage I only saw a couple of small spots, as if he were just testing the wood for insects and found nothing. Thankfully, he hasn’t been back since. We’re hoping it stays that way.

Also, after the siding was up for about a year, especially after its first summer, it started to show some wear. Since the north side has held up the best, I can only assume it’s exposure to the sun that caused most of the wear to occur on the other three sides of the house and garage (although I’m sure rain played its part, too).

north light orange
Although showing some wear, these boards have retained their orange and yellow undertones on the north side of the garage.

In general, areas with a heavier layer of char have held up better, but sometimes even in these areas we’ve seen some missing char develop.

Here are some pictures showing the extent of the fading:

west b4 tar
West facade facing the backyard.
kitchdr19b4
South side.
s east end b4 tar
Another view of the south side.
south garage b4 tar
South side of the garage.
garage b4 tar
East-facing side of the garage.

The wear occurred slowly, so it kind of crept up on us. At some point, both my wife and I started to remark on the changes. And some areas are far worse than others:

close up missing char
Arguably the worst area of fading on the charred cedar.

Although the charred wood wasn’t in any immediate danger, and I enjoyed this ‘aged’ look, my wife said she preferred the original, more opaque, black look of the siding. And to be honest, since many of these exposed areas were turning gray, I worried about how well any product we might try in the future would soak in and adhere, so I decided to address it this year rather than wait any longer.

Thankfully, I was aware of Kent’s blog, Blue Heron Ecohaus, having seen it featured on GBA. He goes into detail regarding his decision to use Auson black pine tar instead of going with a shou sugi ban finish.

Our siding was installed in the Fall of 2017, and last summer I experimented with the recommended 50/50 mix of Auson and linseed oil, using it to touch-up a handful of boards, including all the cut edges that Wojtek and Mark had meticulously burned. Without any tung oil, these exposed edges had faded badly, almost to the same consistent gray on every piece. Again, this may be because they didn’t receive an especially heavy level of char when burned, but I can’t know for sure.

The guy in this video had a lot more fun applying the product than I did:

Even though the charred wood is said to easily last for decades, we also knew that it should get oiled about every 15 years to improve its durability, so having to do touch-ups wasn’t as heartbreaking as it might otherwise have been. I guess our 15 year mark came early. It also helped that it wasn’t necessary to do any overhangs (fascia or soffit) — those areas seem to be holding up really well, including the areas of ‘tiger striping’.

tiger striping on south overhangs
Area of fascia and soffit on the south side of the house with ‘tiger striping’.

A second view of the eaves with the ‘tiger striping’, along with the soffit vent, gutter and downspout, and, if you look closely enough, a moth hanging out on the Kwikmesh screen:

Here are some pictures of the ‘refreshed’ charred cedar:

w sw as pine tar being applied
Starting on the west side with the black pine tar.
pine tar fmly rm wdw - bleached out to rgt
Making progress on the south side.

Our little black box with revitalized skin:

w after tar evening
West facade complete.
south west fmly rm after tar
Southwest corner after pine tar.
south tower after tar
Another view of this southwest corner.
porch after tar
Front entry and the south side of the garage after pine tar.
front after tar
Another view of the east facade after the pine tar.
708 after tar
Closer view of the charred cedar after the pine tar.
close up char texture after tar
Close-up: the black pine tar had no negative impact on the heavily charred areas.
after tar still variation color texture
On areas with the lightest char the black pine tar soaked in but didn’t completely make the surface an opaque black. My guess is, a second coat probably would’ve made it opaque.

If I was going to do charred cedar, or shou sugi ban, again — at this point, that’s a big ‘if’ — I would definitely insist on doing a uniformly heavy char finish (or ‘gator’ finish), and I would use the black pine tar to try and seal-in the char as much as possible. As beautiful as the lighter charred areas were when they first went up, they just couldn’t stand up to the weather — at least that was our experience anyway.

black box in snow1
Our little black box in snow. Another reason we chose to go with black siding.

Nevertheless, the pieces of shou sugi ban that we’ve incorporated into our interior have held up nicely with just a tung oil finish, showing no signs of deteriorating, presumably because they’ve avoided any direct sun or rain (more on these areas in a future post).

black box in snow2
We like the solidity that the black siding gives to the house when there’s snow on the ground.

Another option would be to use a metal siding version of charred wood:

Bridgersteel

I’m guessing it’s expensive, but it could be a viable alternative, especially for those unwilling or unable to do maintenance chores for the charred wood siding over time but who are, nevertheless, in love with the look of real shou sugi ban.

Still another product worth considering:

Thermory USA

This product is newer, so its long-term durability is still debatable until time proves definitively one way or the other, although the idea does seem promising.

black box snowing
House as the snow falls. We enjoy the sharp contrast between the snow and the black siding.

On a bad day — like when I had to hunt down carpenter bees, or touch-up the char with the pine tar — I know I should’ve gone with a more care-free siding material like metal. And yet, on most days, when the overhangs and siding are perfectly fine, it’s hard to argue against the singular look that charred cedar can produce.

sd at kitch dr at night
Kitchen door and stoop with the light on.

So even with all the time, effort, money, and frustration that’s gone into making the charred cedar work, I still love the way it looks every time I pull into the driveway, or notice it while working in the yard. It’s just important to understand that as with anything worth doing, or any labor of love — like building our house it could be said — it comes at a price.

frt dr w: light
The house at magic hour.

Building in the Suburbs

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Once you’ve decided to pursue a new construction build, regardless of where you buy land, it’s likely to raise some issues regarding unintended consequences (whether or not the homeowner, builder, or developer wishes to acknowledge this is another matter).

In a rural setting, for example, you’re likely to be removing fertile farmland, or cutting down someone’s idea of a pastoral idyll or enchanted forest.

Look out the plane window on a flight from New Orleans to Chicago, or Denver to Cincinnati. Everything you see is already in agricultural production. This huge expanse of naturally fertile ground literally feeds the world. The suburbs growing around any city show that we are losing agricultural land even as the human population continues to grow. 

— David R. Montgomery, Dirt: The Erosion of Civilizations

With nature setting limits on land viable for agriculture, future generations may be horrified by our willingness to build over these acres of fertile soil with so little thought for the potential long-term consequences.

Many of Wendell Berry’s essays lament this lack of respect for the land, whether it’s cultivated field or wild forest:

In a larger city, on the other hand, you might be tearing down something people find historically significant, or maybe just significant to the character of a specific block or neighborhood.

Building in the suburbs, even when it’s done on a previously empty infill lot in a well-established subdivision like ours, still comes with its own set of unique implications.

For example, at one extreme there is a great fondness for suburbia, even a kind of utopian idealism.

It’s not uncommon at this point in their history for this idealism to be wrapped up in fond childhood memories, eliciting a vibrant strain of nostalgia (some might suggest of an unhealthy, cloying variety) for suburban life.

All too often suburbia is just the unquestioned background for mainstream life, for example, in the string of popular 1980’s films by John Hughes:

Although it’s hard not to notice in this case, at least, that the main characters escape from the suburbs to the big city when they’re in the mood for some excitement, adventure, and cultural enrichment.

At the other end of the spectrum there is utter contempt for suburbia and its perceived values, readily apparent in any number of movies, novels, or the DIY Punk movement of the late 1970s and early 1980s (and still going strong).

From this perspective, the suburbs are where the soul goes to die (particularly for the adults who have made their peace with authority, or so the argument would run). In other words, there may be safety in the suburbs, but it comes with a price. In fact, for many of its critics, suburbia represents mostly denial rather than any kind of meaningful affirmation.

The Revolutionary Hill Estates had not been designed to accommodate a tragedy. Even at night, as if on purpose, the development held no looming shadows and no gaunt silhouettes. It was invincibly cheerful… A man running down these streets in desperate grief was indecently out of place.

— Richard Yates, Revolutionary Road

For many young people the suburbs are what you end up trying to escape. The suburbs are missing something; the only thing on offer is the bland, the same, the quiet, and the sleepy. At best the suburbs in this case can be thought of as an uncomfortable launching pad, or a spur motivating escape plans. Your dreams and aspirations lie elsewhere, and the sooner you can move on the better.

As far apart as these two extremes might appear, feelings about the suburbs can even fall somewhere in-between (especially for those of us who were raised in suburbia), as a kind of bittersweet mix of love and contempt — e.g. ‘I didn’t choose to grow up in the suburbs, but that’s where many of my most vivid memories reside‘.

Early on in his 33 1/3 study of Arcade Fire’s album The Suburbs, Eric Eidelstein makes a similar point, “There’s nothing I wanted more than to leave my suburban upbringing. Now that I have, a part of me wishes I could dip my toes back into the bubble… Suburbia is innocence and ignorance… freedom and constraint… lightness and darkness.” The key, and devastating, word in that passage being ‘bubble’.

This Smashing Pumpkins song and video captures a similar feeling:

Two wildly different episodes from the original Twilight Zone TV-series reflect these violently divergent attitudes towards suburbia. The first is a love letter to a golden childhood, forever lost to the passing of time and the realities of adulthood. The second represents a kind of hell of conformity, reeking of paranoia and dread. Civility is revealed to be only a thin veneer that easily falls away under the slightest pressure, exposing ugly truths buried just below the surface of everyday life. For anyone who grew up in the suburbs these storylines are relatable, no doubt to varying degrees.

Walking Distance:

The Monsters are Due on Maple Street:

In my own case, living in the suburbs entailed countless hours of playing various sports with friends in the neighborhood, and seemingly endless bicycle rides through contiguous subdivisions waiting for the day we could drive cars (or ride motorcycles) and actually go somewhere, alongside memories of the ‘perfect’ neighbors who, later it was revealed, had separately engaged in fraud and embezzlement at work, seemingly out of unadulterated greed since neither of them ‘needed’ the money.

Perhaps no other work better captures this strange mixture of paean and warning about what lays just below the surface in the suburbs than David Lynch’s Blue Velvet:

For decades Americans have abandoned small farming communities and larger metropolitan areas to flee to the suburbs, mainly in the hopes of rounding off the sharp edges of life as it’s experienced on a farm or in a large city.

The suburban ideal offered the promise of… an environment that would combine the best of both city and rural life.

—Kenneth T. Jackson, Crabgrass Frontier

What was clearly being left behind were the extremes. For example, brutal — albeit beautiful at times — farm life:

Days of Heaven:

Dawn to Dusk:

And the seemingly cartoonish, but no less lethal, aggression often associated with the big city:

The Warriors:

Mean Streets (NSFW):

As Jackson notes in Crabgrass Frontier, the suburbs “offered the exciting prospect that disorder, prostitution, and mayhem could be kept at a distance, far away in the festering metropolis.” Simultaneously, although nurturing a carefully manicured lawn (a practice that dates back to at least the 19th century), the average suburban plot freed its owner from the back-breaking labor associated with farming, along with its attendant risks like crop failures, the vagaries of maintaining livestock, or the whims of the marketplace.

In staking out a middle ground, suburbia tries to avoid the excessive “liveliness” of the big city, while also studiously avoiding the brutal cycles of life and death that anchor and allow a working farm to thrive. Nevertheless, suburbia remains tethered to city and farm; almost entirely dependent on the city’s industry and markets (both for employment and consumption), while the farms supply virtually all of its food supply. In a way, then, suburbia represents both a denial of life and death.

But the extremes are no less real, and they remain virtually impossible to avoid altogether. Denial just makes the situation worse.

In the case of Blue Velvet, for instance, where the villain, Frank Booth, is presented as evil incarnate stalking around the suburbs at night, things may be even worse than they first appear. As David Foster Wallace points out, “…the real horror in the movie surrounds discoveries that Jeffrey makes about himself… not of Dark Frank but of his own dark affinities with Frank is the engine of the movie’s anxiety.” Lynch, according to Wallace, drives this point home in the car scene when Frank turns back to Jeffrey and says “‘You’re like me’. This moment is shot from Jeffrey’s visual perspective, so that when Frank turns around in the seat he speaks both to Jeffrey and to us [emphasis added].”

If the suburbs at their worst represent an attempt to push away harsh realities, then it can’t go on forever, and, in the meantime, the attempt itself can produce some pretty nasty consequences.

This kind of angst in the suburbs almost seems inbred at this point; not only has it survived but it’s thrived for decades, seen in the boredom and unfocused rage of Rebel Without a Cause right up to the grunge and riot grrrl movements of the early 90’s and beyond.

The chicken run from Rebel Without a Cause:

Bikini Kill’s Rebel Girl:

Meanwhile, the kind of human wreckage detailed in Madeline Levine’s The Price of Privilege is clearly deeply rooted in suburban realities and conventional notions of what constitutes success and ‘the good life.

As a result, reasons for disliking the suburbs are legion, especially evident once you start looking for opinions. Moving beyond the general stereotypes of conformity and isolation, there are also stark realities regarding how suburbia came to be and how it’s been maintained, which is especially devastating when you realize nothing was a foregone conclusion, and that choices have been made at every stage of their progression.

In confronting “The prevailing myth… that the postwar suburbs blossomed because of the preference of consumers who made free choices in an open environment,” Jackson points out that “Because of public policies favoring the suburbs, only one possibility was economically feasible.” Once government programs like “FHA and VA mortgage insurance, the highway system, the financing of sewers…”, not to mention “…the unusual American practice of allowing taxpayers to deduct mortgage interest and property taxes” are taken into account, the suburbs seem not only inevitable but carefully planned for — even if many of their long-term consequences were not.

Understanding this historical context makes a work like Family Properties even more of a heartbreaking read. Whether it’s the well-documented history of red lining, blockbusting, ‘contract selling’, restrictive covenants, or even more publicly overt acts of racism, the suburbs certainly have an ugly past.

As Beryl Satter makes clear, being forced to ‘buy on contract’ meant African Americans lost “their savings during the very years when whites of similar class background were getting an immense economic boost through FHA-backed mortgages that enabled them to purchase new homes for little money down… While contract sellers became millionaires, their harsh terms and inflated prices destroyed whole communities.”

In effect, one group of Americans enjoyed the benefits of homeownership, including selling years later for a substantial profit (in many cases passing this money on to a second generation as part of an inheritance), while another group of Americans lost their entire life savings.

And that past, unfortunately, never seems to be very far away.

It is this kind of historical context that helps explain, at least in part, the resonance of a movie like Get Out:

It’s undeniable, then, that the suburbs, as an idea and a physical reality, are overdue for some kind of transformation — in terms of socioeconomic issues, resource demands and energy use, architectural aesthetics, transportation, water management, their relationship to nature (both wild and cultivated), etc. The list of issues that could be addressed is truly daunting.

Here is one attempt:

The suburbs are also dragging around other cultural baggage besides just single-family homes and endless miles of congested highways. For instance, it’s almost impossible to bring up suburbia without acknowledging the rise and fall of the shopping mall, at least the dominant style of mall popular since the second half of the 20th century:

As others have clearly documented (perhaps most vividly by Dead Malls), many of these shopping malls look to be on their way out, as both cultural touchstones and architectural objects:

In their place, one proposed solution is Lifestyle Centers. It’s not at all clear that anyone has a definitive, bullet-proof, strategy for overhauling these structures, and ‘lifestyle centers’ appear to be little more than a variation on the original shopping mall form. In fact, it appears cities and developers are just guessing at what might work.

One solution for the suburbs in general might be pockets of self-contained neighborhoods, mimicking the dynamic energy of urban living Jane Jacobs wrote about in Death and Life of Great American Cities, which is reminiscent of many traditional European cities, and even smaller village neighborhoods:

Whether or not the housing density necessary to achieve this is possible (e.g., building up to avoid excessive sprawl, with each individual residential unit smaller than what we’ve grown to think of as normal), it would also require a high-level of city planning and cooperation amongst all the stakeholders to incorporate all the services and day-to-day needs of the population, all while managing to also maintain and hold onto significant green spaces. A tall order indeed.

Even so, there have been pioneers and experiments trying to explore various possibilities.

For example, Village Homes in Davis, California, developed in the 1970’s, pursued a more holistic approach to residential construction.

His comments at the end of the video regarding their battle with the status quo is particularly telling. You can read more about the project here: Village Homes

More recently, the founding partners of GO Logic worked to create Belfast Cohousing Ecovillage.

The hope is that living arrangements and social networks like these will improve the participants’ quality of life.

These kinds of cooperative living and working arrangements are growing in popularity, with a major historical antecedent being Mondragon in Spain.

As Americans grow increasingly disenchanted working for large, unaccountable corporate entities, these kinds of organizations have the potential for significant expansion, even in places like Cincinnati, which is hardly thought of as a progressive redoubt.

South Mountain Company, based on Martha’s Vineyard, would be one successful example from the construction and design fields (Marc Rosenbaum, who’s had a significant presence on GBA, is one of their employees/co-owners). John Abrams, the founder, wrote Companies We Keep, a compelling and detailed read on the evolution of the business.

For anyone who’s interested, the US Federation of Worker Cooperatives is an excellent resource for those wanting to pursue this idea further.

There are still other projects, for instance, community gardens or larger scale suburban permacultureguerrilla gardening, or even Brad Lancaster’s street project, which try to improve the quality of life at the neighborhood level of a subdivision or even a single block (note that it’s no accident that all of these smaller projects improve our connection to nature).

Even something as small as planting a hell-strip on your own with colorful perennials is a start — something we see more and more of in the residential neighborhoods just outside of downtown Chicago, and even out here in the suburbs. Considering their tiny area of square footage, these mini-gardens have an incredibly powerful visual impact.

These projects represent mostly small-scale, but no less valid, attempts to make suburban life better and more meaningful for residents and visitors alike. In addition, these projects point to our intrinsic need for maintaining a real connection with nature, now often referred to with the buzzword notion of Biophilic Design, itself an outgrowth of E.O. Wilson’s biophilia hypothesis.

Almost anything would be preferable to the typical mix of poorly built cookie-cutter homes surrounded by congested roadways and the endless, and largely undifferentiated, strip mall hell that we currently endure:

As with strip malls, if houses prove to be equally unloved, even despised, it’s easy as a culture to let them rot or just bulldoze them and start over. If people are going to put in time, money, and effort to save something, it had better be well-loved, i.e. fulfill some pretty fundamental needs.

The existing and aging housing stock ringing every large city in America isn’t going anywhere. Whether rehabbed in a sporadic and piecemeal way, with varying amounts of success (both in terms of build quality and energy consumption), or the issue is addressed head-on by local and federal programs, something will need to be done.

It’s possible to imagine a large-scale retrofit program, with Passive House, or at least Pretty Good House, goals set as the benchmark. After tearing down the most dilapidated units, making way for the new, there would still be ample opportunity to rehab existing structures in a thoughtful way that could be a real boom for employment (maybe even allowing us to finally establish a much needed national apprenticeship system) as it also works to draw down on our housing stock’s demand for energy. It would also be offering people work that has real, tangible benefits to our society and the world as a whole, something that’s missing from most construction work at the moment.

If one’s intent, however, is just to dismantle the logic of the suburbs, there’s certainly no shortage of intellectual rocks lying around if you want to pick some up and start throwing them through the shiny, glass-filled facade of suburbia.

And frankly, it’s kind of fun to do. For example, how about suburbanites as brain-dead zombies out to mindlessly consume:

Whether it’s their costly infrastructure and massive energy consumption, their car dependency, their love affair with lawns, their lack of density, their total isolation from farming (or nature more generally; even where it does pop up it tends to look and feel like an afterthought), or the isolation from what the city has to offer, the suburbs certainly have their issues, many of them profound if not existential.

And even though I think all of these issues are certainly well worth thinking about, especially if you have the ability to choose between rural, urban, and suburban locations for work, the fact remains that for many people the suburbs are, in fact, still the best option for housing.

So the question remains: How do we make the suburbs better? 

In our case, my wife works less than ten minutes from home. Unfortunately, a car is still the only real option for transportation (rather unbelievably) — e.g., busy roadways and a lack of continuous pedestrian or cycling pathways make what is an otherwise short commute somewhat perilous to navigate. Nonetheless, moving into Chicago proper, or out to a rural setting, didn’t make much sense to us, mainly because of the added drive time.

After deciding that we would try and build something new here in Palatine, a suburb of Chicago, we concluded that we should do our best to make something that would be loved and cared for long after we’ve moved on.

For the house itself this meant making choices regarding the structure, while for the yard, at least in our case, it meant pursuing permaculture principles rather than the more typical suburban lawn with some foundation plantings (more on the specific details in future posts).

Obviously, one house here or there that bucks current trends isn’t going to change much about an entire culture. A house like ours is mostly just to demonstrate what’s possible. Nevertheless, there’s real opportunity for large scale change, whether in our bigger cities, rural areas, or even the suburbs.

In the cities it could mean carving out space for many more community gardens, insisting on Passive House (or at least Pretty Good House) structures, limiting the use of cars while overhauling public transportation, all while giving priority to pedestrians.

Also, coming up with various strategies to avoid gentrification so that once a neighborhood is fully revitalized the original, long-term residents aren’t forced out by a higher cost of living (mainly through increased rents and property taxes).

As Aaron Shkuda documents in his book The Lofts of SoHo (Gentrification, Art, and Industry in New York, 1950-1980), a large influx of artists and the culturally much-maligned ‘hipsters’ is typically the initial spark a struggling neighborhood needs to begin a turnaround.

“The form of development that artists pioneered in SoHo provided a way for cities to confront the urban crisis without the financial and social costs of slum clearance… the mode of development that grew in SoHo was the antithesis of urban renewal. It was unplanned, and it stymied the attempts of experts or politicians to control it… SoHo provided a distinctly urban alternative to the structures built through urban renewal. These projects mainly attempted to provide urban residents with amenities found in the suburbs, such as easy auto access, security, and a verdant, non-urban feel. SoHo was gritty, urban, dense, and all the more popular for it… the history of SoHo demonstrates that it is perhaps the neighborhoods that artists create, rather than the artists themselves, that help draw and retain [educated professionals].” 

—Aaron Shkuda, The Lofts of SoHo

In fact, as Shkuda points out, this formula has repeatedly proven so successful that “it is difficult to find a contemporary American city without residential lofts.” In effect, large, empty or abandoned, spaces converted into residential lofts is a stamp of approval, announcing that a specific neighborhood is now desirable or even the height of ‘cool’.

The trick is making sure the transformation — making an area worth going to because of art galleries, artisan shops, unique restaurants, bars and coffee shops, and overall cultural vibe — doesn’t overshoot the mark, moving past rebirth to a stage where only the wealthy can afford to stick around and participate.

Moreover, the fact that SoHo emerged from the ashes of deindustrialization not through centralized planning but rather the hard work and vision of individuals is worth celebrating. More importantly, it’s worth remembering as others take on the largely thankless task of urban renewal in their own neighborhoods (perhaps much the same applies to rural and suburban areas: if you want something different, make it different).

In rural areas we could encourage a transition from factory farms to a more holistic agroforestry model (hopefully inspiring some young people to come back from the city and suburbs to pursue a viable and rewarding career in farming). This model could include ample opportunities for agro-tourism, both to benefit locals and those who will visit from the suburbs and cities.

In the suburbs, in addition to renovating aging housing stock (again, to Passive House or Pretty Good House levels of performance), the development of walking and cycling trails, not unlike the Atlanta Beltline, for example, which would include walkable areas that thoughtfully combine residential and commercial zones, all while remaining focused on our need for nature via biophilic design strategies, could be the transformation that allows the suburbs to move beyond well-earned, but stale, cliches.

In addition, the suburbs require not just a new vision regarding mixed use, but also mixed income, providing housing to all, whether poor, old, young, or its more traditional economically secure nuclear families.

Unfortunately, if the glacial rate of change from conventional to ‘green’ building techniques in the construction industry is any indicator, then the suburbs may just carry on doing their thing, loved by some as they alienate and agitate others, all while remaining quietly, but defiantly, resistant to change.

Siding Part 1: Continuous Insulation with a Rainscreen

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Continuous Insulation vs. Double-Stud Wall

Although builders can make either approach to high-performance walls work, we decided continuous insulation (or CI for short) made the most sense to us. And while continuous insulation has its own challenges, especially in terms of air and water sealing details around windows and doors, intuitively we felt insulation on the outside of our sheathing would give us our best chance at long-term durability for the structure.

In spite of the fact that these kind of wall assemblies are climate specific, for anyone interested in the performance of various wall assembly approaches this BSC paper is an excellent place to start:

High R-Walls

Or you can check out Hammer and Hand’s evolving wall assembly strategies here:

Passive House Lessons

And here’s a mock-up wall assembly by Hammer and Hand showing many of the details we incorporated into our own house:

While many believe a double stud wall simplifies much of the framing, we decided that a continuous insulation approach, which in theory should better manage seasonal moisture changes inside the walls while it also eliminates thermal bridges, was worth the extra effort.

2 Layers of Rockwool over Zip Sheathing

Based on the drawings from our original builder, Evolutionary Home Builders, who was going to use 3.75″ inches of rigid foam, and the recommendations of both PHIUS and Green Building Advisor for our climate zone 5 location (leaning heavily towards PH performance), we decided to go with 4″ of Rockwool Comfortboard 80 on top of our Zip Sheathing.

For more information regarding how we came up with the specifics of our wall assembly, go here:

Wall Assembly

Finding Subcontractors for a Passive House

In the Chicagoland area it’s still a struggle to find builders or subcontractors who are knowledgable about, or even interested in, “green building”. In fact, despite our well-documented experience with Evolutionary Home Builders, clients continue to hire Brandon Weiss (Dvele and Sonnen) and Eric Barton (apparently now on his own as Biltmore Homes, or Biltmore ICF) presumably because the options here in Chicago remain so limited. We assume this is the case because we still get the occasional email from current or former clients who have also had a negative experience working with Brandon or Eric. In addition, even though PHIUS has dozens of certified builders and consultants listed for Illinois and the larger Midwest region, it’s unclear just how many of them have worked directly on an actual Passive House project.

Until there’s more demand from consumers, or the building codes change significantly, it’s difficult to imagine the situation improving much in the near future. This is unfortunate since particularly here in the Chicago area, or the Midwest more broadly, homes could really benefit from the Passive House model, or something close to it, e.g. The Pretty Good House concept, because of our weather extremes (dry, cold winters and hot, humid summers). The combination of meticulous air sealing, high R-values, and continuous ventilation associated with any high-performance build is hard to beat in terms of day-to-day occupant comfort, not to mention the significant reduction in both overall energy demand and the cost of utilities.

In our own case, when I think of all the individual trades we had to hire, securing a siding contractor was far and away the most difficult. Our HVAC contractor for the ductless mini-splits was already somewhat familiar with “green” building and PH, so working with me on air sealing details and dealing with a thick wall assembly didn’t worry him. Also, if I had it to do over, I don’t think I’d bring up all the PH details with a plumbing or electrical contractor when getting bids since the air sealing details are pretty straightforward and can easily be planned for and executed on-site after they begin their work (assuming someone else, most likely a rough carpenter, GC, or homeowner is tasked with all the air sealing chores). And if the concrete sub is unfamiliar with insulation under a basement slab, or over the exterior walls of the foundation, then it’s easy enough for framers, or even homeowners if necessary, to do this work, along with installing a vapor barrier like Stego Wrap before the basement slab gets poured.

For siding, however, because of the level of detail involved before the siding itself could be installed, it was a real challenge to even get quotes. As things turned out, we had nearly twenty contractors (a mix of dedicated siding contractors and carpenters) visit the job site before we received an actual estimate. Many of those who visited the job site expressed genuine interest, most going so far as to acknowledge that this kind of wall assembly made sense and would probably be mandated by the residential code at some point in the future, but almost without exception they would disappear after leaving the job site — no bid forthcoming, and no response to my follow-up phone calls or emails.

Clearly they were terrified, not without justification, to tackle something so new, viewing our project through a lens of risk rather than as an opportunity to learn something new. From their point of view, why not stick with the type of jobs they’ve successfully completed hundreds of times in the past? It also didn’t help that I was a first time homeowner/GC, rather than a GC with a long track record of previously built homes in the area.

In addition, not only is continuous insulation over sheathing a novel concept in the Chicago area, especially in residential builds, even utilizing a ventilated rainscreen gap behind siding is almost unheard of — typically Hardieplank lap siding is installed directly over Tyvek or similar housewrap (this can be observed directly on hundreds of job sites across the city and suburbs). And this isn’t entirely the fault of contractors. For instance, how many homeowners when presented with the idea of continuous insulation, or a rain screen gap, balk at the extra costs associated with these techniques without carefully considering the potential energy savings or increased durability for the structure?

While there are any number of certified LEED projects in our area, and even some Passive House projects (both residential and commercial) in Chicago and the surrounding suburbs, for the most part consumers are still largely unaware of Passive House or other “green” building standards like Living Building Challenge. Clearly “green” building, let alone Passive House, has its work cut out for it here in the Midwest if it ever hopes to have a meaningful impact on the construction industry.

Installing Rockwool over the Zip Sheathing

Mike Conners, from Kenwood Passivhaus, was nice enough to recommend Siding and Window Group, which definitely got us out of a jam. Thankfully, Greg, the owner, was up for the challenge and was nice enough to let us work with two of his best guys, Wojtek and Mark.

Initially Wojtek and Mark dropped off some of their equipment at the site the day before they were to start work on the house. This gave me a chance to go through many of the details with them directly for the first time. Although a little apprehensive, they were also curious, asking a lot of questions as they tried to picture how all the elements of the assembly would come together. In addition to the construction drawings, the series of videos from Hammer and Hand regarding their Madrona Passive House project were incredibly helpful (this project in particular was a big Building Science inspiration for us).

Also, this video from Pro Trade Craft helped to answer some of the “How do you…?” questions that came up during the design and build phases:

As sophisticated and intricate as some architectural drawings may be, in my experience nothing beats a good job site demonstration video that shows how some newfangled product or process should be properly installed or executed.

On the first day, while Wojtek and Mark installed the Z-flashing between the Zip sheathing and the foundation, along with head flashings above the windows and doors, I started putting up the first pieces of Rockwool over the Zip sheathing.

installing head flashing above wdw
We found it easier to embed the metal flashings in a bead of Prosoco’s Fast Flash. Once in position, an additional bead of Fast Flash went over the face of the flashing, ensuring a water tight connection between the metal and the Zip sheathing.

For the first layer of Rockwool we installed the pieces horizontally between studs as much as we could, knowing that the second layer of Rockwool would be oriented vertically. This alternating pattern helps to ensure seams are overlapped between layers so there aren’t any areas where the seams line up, an outcome that could undermine the thermal performance of the 2 layers of Rockwool.

z flashing nw corner
Z-flashing carried down over the exposed face of the Rockwool on the outside of the foundation walls — once installed, the gravel is pushed back so it covers the area where the flashing terminates on the face of the Rockwool. The other 3 sides of the house had much less exposure in this foundation-gravel border connection.

We didn’t worry too much about the orange plastic cap nails missing studs since they were sized to mostly end up in the Zip sheathing. In the end only a couple of them made it completely through the Zip without hitting a stud.

1st pcs rockwool going up n side
Putting up the first pieces of Rockwool on the north side.

Every so often Wojtek would come around the corner and watch what I was doing before asking questions about specific elements in the wall assembly.

orange cap nails for 1st layer rockwool
Plastic cap nails we used to attach the first layer of Rockwool. I purchased these from a local roofing supply house.

By the time I had about a quarter of the north side covered, Wojtek and Mark were ready to take over from me.

1st layer rockwool n side
First layer of Rockwool mostly complete on the north side. Before installing the bottom row of Rockwool we used shims to create a slight gap between the Rockwool and the metal Z-flashing on the foundation insulation to allow any water that ever reached the green Zip sheathing a clear pathway out.

In a pattern that would repeat itself with each layer of the remaining wall assembly, Wojtek and Mark would carefully think through the details as they progressed slowly at first, asking questions as issues arose, before getting the feel for what they were doing and eventually picking up speed as they progressed around each side of the house.

20171002_081038
Outside corner showing the Z-flashing covering the face of the Rockwool on the foundation with the first layer of Rockwool covering the Zip sheathing above.

Working through the many details with Wojtek and Mark — the majority of which occur at junctions like windows and doors, the top and bottom of the walls, along with mainly outside corners — was both collaborative and deeply gratifying. They demonstrated not only curiosity and an ability to problem solve on the fly, they also clearly wanted to do things right, both for me as a customer and for the house as a completed structure (it felt like both aesthetically and in building science terms).

1st layer rockwool at wdw buck
First layer of Rockwool meeting up with a plywood window buck. We tried to keep connections like these as tight as possible, especially since the window buck itself already represents a slight thermal bridge.

They never hurried over specific problem areas, arrogantly suggesting they knew better, instead they patiently considered unanticipated consequences, potential long-term issues, and actively questioned my assumptions in a positive way that tried to make the overall quality of the installation better. This mixture of curiosity, intelligence, and craftsmanship was a real pleasure to observe and work with.

starting 2nd layer rockwool n side
Mark and Wojtek beginning the second layer of Rockwool on the north side.

If a GC built this level of rapport with each subcontractor, I can certainly understand their refusal to work with anyone outside of their core team — it just makes life so much easier, and it makes being on the job site a lot more fun.

2nd layer rockwool at utilities
Second layer of Rockwool installed around mechanicals. Note the sill cock, or hose bibb: although it runs into the house, we left it loose so that it could be adjusted until the siding was complete — only then was it permanently soldered into place.
weaving outside corner w: 2nd layer
Weaving the seams at the outside corners to avoid undermining the thermal performance of the Rockwool.
2nd layer rockwool fastener at wdw
Close-up of the fasteners we used to attach the second layer of Rockwool.

For the second layer of Rockwool, Wojtek and Mark tried to hit only studs with the black Trufast screws. In fact, screwing into the studs with these fasteners, in effect, became a guide for accurately hitting studs with the first layer of strapping.

plates for 2nd layer rockwool

These Trufast screws and plates worked well and were easy for Wojtek and Mark to install.

trufast screw bucket
inside bucket trufast screws
The Trufast screws and plates were purchased from a local roofing supply house.
w side 2 layers rockwool
West side of the house with 2 layers of Rockwool complete.
1st layer rockwool into s side garage
First layer of Rockwool filling the gap between the house and garage framing.

If our lot had been larger, we would’ve gone with a completely detached garage, but unfortunately it just wasn’t an option.

2nd layer rockwool closing gap at garage
Second layer of Rockwool closing the gap between house and garage completely, ensuring our thermal layer is unbroken around the perimeter of the house.
nw corner 2 layers rockwool
Northwest corner of the house with the 2 layers of Rockwool installed.

It was exciting to see the house finally wrapped in its 4″ of Rockwool insulation.

Installing Battens and Creating our Rainscreen

Initially we were going to use 2 layers of 1×4 furring strips (also referred to as strapping or battens); the first layer installed vertically, attaching directly over the 2×6 framing members through the 2 layers of Rockwool and the Zip sheathing, with the second layer installed horizontally, anticipating the charred cedar that would be oriented vertically on the house.

Pro Trade Craft has many really informative videos, including this one on using a rainscreen behind siding:

Nevertheless, as the second layer of Rockwool went up, Wojtek and Mark pointed out that putting the siding in the same plane as the Rockwool/metal flashing on the basement foundation would be needlessly tricky. In other words, maintaining about a 1/8″ horizontal gap between the bottom edge of the vertical siding and the metal flashing on the foundation around the house would be nearly impossible, and any variation might prove unsightly.

As a solution, we decided to use 2×4’s for the first layer of strapping. By adding to the overall thickness of the remaining wall assembly it meant the eventual siding — now pushed slightly out and farther away from the Z-flashing covering the face of the Rockwool on the foundation — could be lowered so that visually it slightly covered what would’ve been a gap between the top of the metal flashing on the foundation insulation and the bottom edge of the siding. Wojtek and Mark also found that the 2×4’s were easier to install than the 1×4 furring strips directly over the Rockwool so that it didn’t overly compress the insulation (an easy thing to do).

Unfortunately, increasing the overall wall thickness with 2×4’s meant having to use longer Fastenmaster Headlok screws (it would also cost us later when it came to the siding on the north side of the house — more on this later). Apart from this change, the additional overall wall thickness mostly just increased the air gap in our rainscreen, which arguably just increased potential air flow while also expanding the drainage plane behind the eventual siding.

In one of the Hammer and Hand videos Sam Hagerman mentions that at least 1.5″ of screw should be embedded into the framing (excluding the thickness of the sheathing) for this type of wall assembly, but when I asked a Fastenmaster engineer about this directly he recommended a full 2″ of their screws should be embedded into the framing members in order to avoid any significant deflection over time.

As a result, we ended up using 8.5″ Headlok screws. The screws work incredibly well, requiring no pre-drilling, and they’re fun to use with an impact driver (keep your battery charger nearby). Along with the plastic cap nails and Trufast screws, I think we ended up with less than a dozen fasteners that missed the mark for the entire house — a testament to Wojtek and Mark’s skill. I was able to seal around these errant fasteners from the inside with a dab of HF Sealant.

headlok missed framing
Sealing around a Headlok screw that missed a 2×6 framing member.

During the design stage, using these longer screws prompted concerns regarding deflection, but based on this GBA article, data provided by Fastenmaster, along with some fun on-site testing, the lattice network of strapping (whether all 1×4’s or our mix of 2×4’s and 1×4’s) proved to be incredibly strong, especially when the siding material is going to be relatively light tongue and groove cedar.

For the garage, since insulation wasn’t going to cover three of the walls (only the common wall with the house was treated as part of the house wall assembly), we used significantly shorter Headlok screws for the first layer of furring strips.

monkey on furring strips
The Beast testing out the structural integrity of our strapping on the garage. Note the Cor-A-Vent strip below the bottom horizontal furring stip, helping to establish a ventilated rainscreen.
garage only 2x4s
Common wall inside the garage. Only a single layer of strapping was necessary in preparation for drywall.

Mark took the time to recess these screws to make sure they didn’t interfere with the eventual drywall.

recess 4 screws
Recessed Headlok screw on a 2×4 in the garage. Ready for drywall.

A small detail, but one of many examples showing Wojtek and Mark’s attention to detail, not to mention their ability to properly assess a situation and act appropriately without having to be told what to do.

Once the 2×4’s were all installed vertically through the structural 2×6’s as our first layer of strapping, Wojtek and Mark could install the components of the rainscreen, including the Cor-A-Vent strips at the top and bottom of the walls, as well as above and below windows and doors. In combination with the 2×4’s and the 1×4’s, this system creates a drainage plane for any water that makes its way behind the siding, while also providing a space for significant air flow, speeding up the drying time for the siding when it does get wet.

rainscreen2.jpg
Why use a rainscreen? Illustration courtesy of Hammer and Hand.

In addition to the Cor-A-Vent strips, we also added window screening at the bottom of the walls just as added insurance against insects. We noticed that on the garage, even without any insulation, the Cor-A-Vent didn’t sit perfectly flat in some areas on the Zip sheathing. Since the Rockwool on the foundation, now covered by the metal flashing, was unlikely to be perfectly level, or otherwise true, along any stretch of wall, it made sense to us to double up our protection in this way against insects getting into the bottom of our walls at this juncture.

starting 1x4s n side
1×4’s being installed horizontally on the north side in preparation for the charred cedar that will be installed vertically. Also note the Cor-A-Vent strips just above the foundation and below the window.
cor-a-vent-product-label
The main product we used to establish our ventilated rainscreen.
insect screen for rscreen
Window screen we cut to size for added insurance at the bottom of the walls around the Cor-A-Vent strips.

Wojtek and Mark also did a nice job of taking their time to shim the 1×4 layer of furring strips, thus ensuring a flat installation of the charred cedar.

shims behind 1x4s
Shims behind some of the 1×4 furring strips to ensure a flat plane for the vertical cedar siding.

This really paid off, not only making their lives easier when installing the tongue and groove cedar, but also providing aesthetic benefits in the overall look of the siding. This was especially true on the north side of the house, which has the largest area of charred siding with almost no interruptions, apart from a single window. It’s also the tallest part of the house, so without proper shimming the outcome could’ve been really ugly. Instead, once the cedar siding was installed it was impossible to tell there was 4″ of Rockwool and 2 layers of strapping between it and the Zip sheathing.

Really impressive work by Wojtek and Mark.

lking down furring behind rscreen at fdn
Looking down behind the ventilated rainscreen — 2×4, 1×4, with Cor-A-Vent and window screen at the bottom, just above the top of the foundation. This gap behind the siding provides ample air flow for the cedar siding, ensuring that the wood never remains wet for long.
rscreen furring at foundation
Strapping and rainscreen elements around a penetration near the top of the foundation.

Things got somewhat complicated around windows and doors, but once we worked through all the details for one window it made the remaining windows and doors relatively straightforward to complete.

Below you can see all the elements coming together: the window itself, the window buck covered with tapes for air and water sealing, the over-insulation for the window frame, the Cor-A-Vent strip to establish air flow below the window and behind the eventual cedar siding, along with the strapping that both establishes the air gap for the rainscreen while also providing a nailing surface for the siding.

Once most of the siding was complete around each window, but before the 1×6 charred cedar pieces used to return the siding to the window frames were installed, each window received a dedicated metal sill pan. The pan slid underneath the bottom edge of the aluminum clad window frame and then extended out just past the edge of the finished siding (I’ll include photos showing this detail in the next blog post about installing the charred cedar siding).

Here’s a JLC article discussing a couple of options for trim details in a thicker wall assembly with similar “innie” or “in-between” windows:

Window Trim

And here’s a detailed slide presentation by Bronwyn Barry regarding details like these for a Passive House wall assembly:

Sills and Thresholds – Installation Details
wdw rscreen and frame detail
The many details coming together around a window. In addition, each window eventually received a dedicated metal sill pan as a durable way to ward off water intrusion.
from int wdw rscreen and sill
Looking through an open window to the sill and the rainscreen gap at the outside edge. Note the Extoseal Encors protecting the sill of our window buck.
lking down wdw rainscreen
Outside edge of the window sill, looking down into the mesh of the Cor-A-Vent strip with daylight still visible from below.
rscreen at hd flash on wdw
Head flashing at the top of a window with doubled up Cor-A-Vent strips above it.
out corner hd flshng ready for sd
Same area, but with a 1×4 nailed across the Cor-A-Vent, creating a nailing surface for the cedar siding.

Many of the same details were repeated at the top and bottom of our two doorways. Below is a close up of the kitchen door threshold with Extoseal Encors and Cor-A-Vent again, along with additional metal flashing. Once a dedicated metal sill pan was installed (after most of the siding was installed), it felt like we did everything we could to keep water out.

kitch dr prepped 4 sd
Many of the same air and water sealing elements and rainscreen details present around the windows ended up at the top and bottom of doors as well.

In the photo below, you can see the many elements we utilized to try and prevent moisture damage around the front porch. For the door buck itself, I applied Prosoco’s Joint and Seam, both at joints in the plywood and the plywood/Zip sheathing connection, but also between the concrete and the door buck, as well as between the Rockwool and the concrete. We also kept the 2×4’s off the concrete, while also using the Cor-A-Vent strips to establish a ventilated rainscreen so that any moisture that does get behind the siding has ample opportunity to dry out in this area before it can cause any rot.

frt porch prep - rscreen water
Front porch: elements in place to try and prevent moisture damage.
west w: 2 layers battens
West facade prepped for siding.
flashing details on porch
Wojtek and Mark did a nice job with all the metal flashing details around the house — these kind of areas are the unsung heroes of a structure that manages water safely, and unfortunately go largely unnoticed by most homeowners.

In the next blog post I’ll go through the details for the top of the ventilated rainscreen when discussing how the charred cedar siding was installed.

Mark and Wojteck at front door
Mark and Wojtek installing Cor-A-Vent above the front door.

Even without the siding installed yet, it was especially rewarding to see all the underlying prep work involved in finishing our thermal layer and rainscreen come together so nicely.

Mark and Wojtek on the roof
Mark and Wojtek on the garage roof finishing up the battens for the front of the house.

Many thanks to Wojtek and Mark for executing all these details with such skill!

Blower Door (Air Sealing #9 )

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When it was time to schedule our blower door test we considered using Eco Achievers, but we only knew about them because they’ve worked extensively on projects for our original builder, Evolutionary Home Builders. We decided the potential awkwardness, or even a possible conflict of interest, wasn’t worth pursuing their services. An example of guilt-by-association I suppose, one that is probably unfounded but, nevertheless, the strong affiliation with our original builder made it difficult for us to reach out to them for help. They also hired one of Brandon’s former employees (this employee was nothing but nice and professional towards us as we were deciding to part ways with Brandon), which would’ve only added another layer of awkwardness to the situation.

Unsure how to proceed, I looked online and found Anthony from Building Energy Experts. He was able to come out and do a blower door test for us, helping me hunt down a couple of small leaks, so that we ended up at 0.34 ACH@50 for this initial test.

Here’s a Hammer and Hand video discussing the use of a blower door:

On a side note: all of the Hammer and Hand videos, along with their Best Practices Manual, were incredibly helpful as we tried to figure out all the Passive House details related to our build. It’s no exaggeration to say that without Hammer and Hand, the Green Building Advisor website, BSC, and 475 HPBS, our build would’ve been impossible to accomplish on our own. I owe an incredible debt of gratitude to all of these great resources who invest valuable time sharing such a wealth of information.

Below is a Hammer and Hand video noting the importance of properly detailing corners to avoid air leaks:

Because of this video, I sealed all of my corners for the windows and doors like this:

HF Sealant in corners b4 blower door
Adding Pro Clima HF Sealant after completing taping of the corner, just for added insurance against potential air leakage.

I also added some HF Sealant to the lower portion of the windows, since some air leakage showed up in this area with Anthony where components of the window itself come together in a seam.

sealant on wdw components junction
Seam near bottom of window where components meet — sealed with HF Sealant.

The areas where components come together often need special attention.

close up corner and wdw components seam w: sealant
Close-up of this same area — seam in components sealed, along with the bottom corner of the window and the gap between window buck and window.

Even with layers of redundancy in place, in the picture below there was a small air leak still present at the bottom plate – sub flooring connection. A coating of HF Sealant easily blocked it.

Once the stud bays were insulated (after most of the siding was up), the interior walls would eventually be covered with Intello (I’ll cover the details in a future post on interior insulation), adding yet another layer of redundancy for mitigating potential air intrusion.

area of kitchen sill plate leakage
Area of kitchen sill plate leakage.

Anthony didn’t have any previous experience with a Passive House build, so it occurred to me that it might be beneficial to reach out to Floris from 475 High Performance Building Supply (he had already done our WUFI analysis for us), and Mike Conners from Kenwood Property Development to see if there was someone locally who did. Mike is a Passive House builder in Chicago who had already helped me out with some Rockwool insulation when we came up short earlier in our project (the two GC’s we fired repeatedly struggled with basic math), and he was very nice to take the time to answer some other technical questions for me as well.

Both, as it turned out, ended up recommending that I contact Steve Marchese from the Association for Energy Affordability.

Steve would eventually make three trips to the house, doing an initial blower door test after the structure was weather-tight and all the necessary penetrations had been made through our air barrier, a second test after exterior continuous insulation was installed, and a final test after drywall was up to ensure there hadn’t been any increase in air leakage during the final stages of construction.

Steve starting blower door test
Steve setting up the blower door for his first test.

Following Passive House principles for our build, we also followed the same protocols for the blower door tests: Blower Door Protocol

With the structure under pressure from the blower door fan, Steve and I walked around the house while he used a small smoke machine in order to try and find any leaks that I could then seal up.

Steve testing window gasket
Steve starting at the windows. Here testing a window gasket for air leakage.

The gaskets around our windows and doors proved to be some of the weakest areas in the house although, comparatively speaking, it was inconsequential since the overall air tightness of the structure was fairly robust (favorite word of architects).

Steve showing impact of unlocked window
Steve showing me the impact a window in the unlocked position can have on air tightness. The gasket, ordinarily squeezed in the locked position, works to bring the sash and the frame tightly together.
Steve smoke at family rm wdw
Looking for areas around the windows that might need adjusting or additional air sealing.

For instance, even though no substantial air leakage showed up around this kitchen door, during our first winter this same door eventually had ice form outside at the upper corner by the hinges, on the exposed surface of the gasket where the door meets the frame.

Steve at kitchen door

After figuring out how to adjust the door hinges, there was no longer any ice showing up this winter, not even during our Polar Vortex event in late January.

Much the same thing occurred around our front door as well, with the same solution — adjusting the hinges to get a tighter fit at the gasket between the door and the frame.

Steve testing attic hatch
Steve testing the attic hatch for any air leakage.

Steve was nice enough to go around and methodically check all the penetrations in the structure.

Steve testing plumbing vent in kitchen
Steve testing for air leaks around the kitchen plumbing vent and some conduit.
Steve testing for air leaks @ radon stack
Steve testing for air leaks around the radon stack.
Steve @ radon stack close up
Close-up of radon stack during smoke test.

There was one area in the guest bathroom where the Intello ended up getting slightly wrinkled in a corner during installation. With Tescon Vana and some HF Sealant I was able to address it so nothing, thankfully, showed up during the smoke test.

Steve testing wrinkled area of Intello
Steve testing area of Intello that I inadvertently wrinkled during its installation.

After looking around on the main floor, Steve moved down into the basement.

Steve testing for air leaks @ main panel
Checking for leaks at the main electrical panel.
Steve testing for air leaks @ main panel exit point
Checking for leaks at the conduit as it exits the structure.
Steve testing for air leak @ sump pit cap
Looking for air leakage around the sump pit lid.

The lids for the sump pit and the ejector pit were eventually sealed with duct seal putty and some Prosoco Air Dam.

Steve testing for air leaks @ ejector pit
Testing the ejector pit for air movement.
Steve testing for air leaks @ Zehnder exit point
Checking for air leakage around one of the Zehnder ComfoPipes as it exits the structure.
Steve testing for air leaks @ pvc:refrigerant lines
Looking for air leaks around the heat pump refrigerant lines as they exit the structure.
Steve smoke at sump discharge
Checking around the penetration for our sump pump discharge to the outside.

Before the second blower door test, I was able to add some duct seal putty to the lids of the sump and ejector pits.

ejector pump lid w: duct seal
Ejector pit lid with some duct seal putty.

Below is a copy of Steve’s blower door test results, showing the information you can expect to receive with such a report:

Final Blower Door Test Results

For the last two tests Steve used a smaller duct blaster fan in order to try and get a more precise reading for air leakage.

Steve at front door
With Steve just after the initial blower door test was complete.

Steve would be back two more times — once before drywall, and once after drywall — just to ensure we had no loss of air tightness develop in the interim stages of the build (especially after continuous exterior insulation with furring strips were installed).

Here are the final figures noting where we ended up:

0.20 ACH@50 and 106 cfm@50

We are well below Passive House requirements (both PHI and PHIUS), so there was a great sense of relief knowing that all the time and effort put into air sealing had paid off, giving us the tight shell we were looking for. Even so, it was still pretty exciting news, especially for a first build.

And here’s an interesting article by 475 HPBS regarding the debate over how air tightness is calculated for PHI vs. PHIUS projects, and the potential ramifications:

Not Airtight

Dressing up the Basement: Steel Beam and Concrete Walls

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With the Zehnder and the Mitsubishi systems installed, I had some time to kill waiting for the siding guys to start, and for my first blower door test to take place, so I moved on to painting my structural steel beam and the exposed concrete walls in the basement. Apart from a couple of walls for my wife’s office that would eventually be drywalled and painted, and a decorative finish for the concrete floor, these were going to be some of the limited finished surfaces in the basement.

We’re glad we decided to leave the basement ceiling unfinished. In doing so, not only did it mean a more straightforward installation process for mechanicals, it also means if any issues develop in the future we’ll have easy access to identify and solve any problems.

I debated whether or not to spray the basement ceiling — the floor joists and the underside of the sub flooring — but decided that the color change (some shade of gray? black?) wasn’t worth the effort.

Although obviously not to everyone’s taste, we like the unfinished look of the ceiling, especially when combined with the texture of the painted concrete walls and our painted steel beam (not to mention the eventual decorative finish for our concrete floor slab — I’ll go through the details in a future blog post since it was applied much later in the build).

For the beam, I first used a wire brush and some sandpaper to remove any loose and flaking rust. Using a Sherwin Williams primer, their All-Surface Primer tinted gray, I applied a heavy, uniform coat to help prevent the return of any rust in the future (keeping humidity in the basement under control should help a lot in this regard).

beam w: primer and rusty red
After wire brushing off loose rust, priming the beam in preparation for paint.

After priming, I then applied two coats of a Safecoat product, their semi-gloss in Patriot Blue.

Safecoat semi-gloss Patriot Blue for steel beam
Patriot Blue for the steel beam.

If I could do it over, I think I’d use Safecoat primers and paints for almost all of the interior surfaces. For the sake of convenience, since they have stores near me, I mainly used Benjamin Moore’s Aura Matte and Satin for walls and trim, and ended up mostly disappointed with their performance — hiding is pretty mediocre, flashing when you try to do spot touch-ups, and over-priced for the level of quality. Benjamin Moore does a great job with their marketing materials and with the look of their labels, I just wish the same level of thought and attention to detail went into the quality of their finishes.

Safecoat is available at various stores in the US, but unless you want a stock white, tinting may happen at Safecoat headquarters before shipping to individual stores, so there can be a wait involved (check with your local supplier for details).

I had good luck ordering from Green Building Supply in Iowa. After ordering online, the products are shipped directly to the job site or your home. This gives you access to high quality No or Low VOC products that, at least in my case, are otherwise currently unavailable in local hardware or paint stores.

Unfortunately, they can’t ship during cold spells, since the paint could freeze and be ruined. When it was cold and I needed product, I found Premier Paint and Wallpaper just outside of downtown Madison, Wisconsin (about a 2 hour drive for us). They’re a family-owned shop, and it shows. They have a nice selection of Safe Coat products. In fact, their wide range of products from various brands is impressive, and the people who work there are really helpful and just easy to work with. Unfortunately, I haven’t found a similar paint store in my area. Around me, Benjamin Moore (aka JC Licht), Sherwin Williams, and Pittsburgh Paint stores dominate the market. The smaller mom-and-pop stores, for the most part, don’t really exist anymore, which is a shame.

beam w: primer and paint
Paint going over the primer.

The Safecoat products that I’ve used typically have some odor, but what little smell they do have tends to dissipate rather quickly (this is particularly noticeable if you change back to a more conventional coating with more VOCs that may take weeks before its distinct odor finally disappears).

painted beam w: zehnder and hpump
Finished beam.

It’s a shame that so many structural beams end up covered over, normally considered too humble, i.e. ugly, to be left alone. In keeping with our Urban Rustic design aesthetic, we think that if they’re given even just a little bit of attention and care they can prove to be a real visual asset to a space, especially in a basement if a more relaxed, informal look and feel is acceptable or even ideal.

cu paintd beam in basement
Close-up of the painted I-beam.

Leaving the spine of the house exposed like this with a bold color emphasizes the job it’s actually doing, and it honors the material by making it front and center visually in the space, rather than trying to hide it away behind drywall or wood. This seems only appropriate since beams like this help keep a house standing upright.

basement walls primed
Another view of the beam, and the recently primed concrete walls.

Once the beam was completed, I moved on to priming the exposed concrete walls.

beast helping me prime basement
Getting some help priming the concrete walls. She lasted about 15 minutes, at which point it clearly turned into work.

Paint color can be a finicky thing. After priming the concrete walls, I used a Benjamin Moore color, Jute, as the finish coat. In the basement it looks great, exactly what we were looking for: a nice, warm neutral khaki color. Upstairs, however, when I later did a test swatch on the new drywall this same color looked horrible, taking on pinkish flesh tones, so we ended up having to use a different color for most of the first floor. Testing out colors, even in relatively small areas, can save a lot of time, money, and headaches later on.

painted basement walls
Concrete walls after paint.

It was really important to me that the basement foundation walls be left exposed, with no insulation or drywall.

20190831_120510

I wanted all of the texture, imperfections, and overall character of the exposed concrete to be vividly on display. Arguably, once painted, these imperfections become even more pronounced.

20190831_120625
There are a couple of areas of ‘honeycombing’ around one basement window. Under the right lighting, it creates a nice visual effect.
20190831_120205
Areas with exposed conduit were also painted.
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With a good chunk of the basement complete, it was time to move outside and get some work done before the siding began, and before we had our first blower door test performed…

HVAC Part 2: Ductless Mini Split

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System Requirements

The plan for our house was to combine an HRV or an ERV (for a continuous supply of fresh air), with a ductless mini split air source heat pump system for our ventilation, heating, and air conditioning needs. Almost all of the projects I had read about utilized this same combination, especially here in the US.

The only real debate, apart from specific brand options, was whether or not to utilize only one distribution head on our main floor, as opposed to installing multiple heads for a more ‘dialed-in’ level of comfort (e.g. in the basement or the bedrooms).

Our original builder had in our construction drawings one head in the kitchen/family room and one in the basement, which was pretty standard for a Passive House level project. It was, therefore, pretty shocking to find out that our second builder (there were two partners) and their HVAC subcontractor were suggesting a system that was grossly oversized for our needs. You can read about the details here: GBA: Oversized System 

This was just one of many ‘red flags’ that convinced us to move on and GC the project ourselves. It’s also a reminder that old habits die hard, meaning even seasoned contractors, in any trade, need to be willing to learn new ideas and techniques if they want to truly be considered professionals and craftsmen — unfortunately, they’re the exception to the rule, at least in our experience.

One of the disappointments associated with our build is, in fact, the disinterest (in some cases even outright hectoring contempt) shown by various tradespeople in our area for ‘green’ building generally. Doubtless, at least a partial explanation for why much of the Midwest seems so far behind in adopting ‘green’ building techniques, especially when it comes to air sealing, insulation, and IAQ beyond code minimum standards. Hopefully this changes significantly in the coming years.

Consequently, I took Steve Knapp’s advice (from the comments section of my question) and contacted Home Energy Partners (their new name: HVAC Design Pros). Isaac responded quickly and eventually did our Manual J, confirming we needed a much smaller system, one that is more consistent with a Passive House project, or even just a high-performance build more generally.

Here are a couple of Matt Risinger videos detailing a mini split set-up that’s fairly typical for a Passive House or a Pretty Good House (GBA article on the 2.0 version).

Once we were on our own, in addition to going with a Zehnder ERV and a Mitsubishi ductless mini split air-source heat pump system, we also pursued the possibility of using a Sanden heat pump water heater.

After seeing it used on a Hammer and Hand project, we thought it was a really interesting piece of cutting edge technology:

Unfortunately, after getting a quote from Greg of Sutor Heating and Cooling, and a poor response from Sanden regarding questions we had about the system (they were unresponsive to emails), we decided to stick with our Zehnder, the Mitsubishi heat pump, and then go with a Rheem heat pump water heater (going with the Rheem saved us just over $6,000 in initial cost). Hopefully, as it becomes more popular in the US, the Sanden can come down significantly in price, or maybe less expensive copycat products will someday show up on the market.

Greg was initially willing to work with us, even though we were technically out of his service area, when the Sanden was involved, but once it was only a ductless mini split he suggested we find a Mitsubishi Diamond installer closer to us, which we understood. He was nothing but professional, taking the time to answer any number of technical questions and offering what proved to be sage advice regarding various details for our system.

In fact, taking Greg’s advice, we contacted a Diamond installer close to us, but unfortunately the first installer we contacted disappeared when we were trying to get him to communicate with our electrician on installation details (an infuriating and painfully common experience when trying to build a new house — especially one with unconventional Passive House details).

Finding our Installer

At this point, we were lucky to find Mike from Compass Heating and Air. He came out to the job site and we walked through the details together. He proved to be knowledgeable, helpful, detail-oriented, and extremely professional. Installing our Mitsubishi ductless mini split system with Mike proved to be one of the easiest portions of our build. We never felt like we had to look over his shoulder, making sure he got details right, or that we had to constantly confirm that he did what he said he was going to do — in fact, it was the opposite: ‘Mike’s on site, so that’s one less thing I have to worry about’.

Compass truck on site
Mike and his crew at the job site to install our Mitsubishi ductless mini split system for heating and air conditioning.

Mike also confirmed what Greg and Isaac also pointed out: comfort issues may develop if we tried to get by with just one distribution head on the main floor.

In fact, looking back through old emails, Greg was nice enough to walk me through some of the options employed by those trying to get by with a single head for an entire floor (sometimes even two floors), including leaving bedroom doors open throughout the day (ideally, even at night), and even the use of Tjernlund room-to-room ventilators.

Again, to his credit, Greg tried to stress how important it was that homeowners have realistic expectations regarding the overall effectiveness of these techniques and options.

He also was at pains to make clear how the work of any competent HVAC installer can be easily undermined by a structure that underperforms. In other words, they can design an appropriately sized HVAC system for a Passive House, but if shortcuts occur during the build and the final blower door number comes in higher than expected, or the budget for insulation gets cut, reducing R-values in the structure, then the system they designed has little chance of working as intended. Based on what he wrote, I’m guessing he has dealt with exactly this outcome in the real world — not fun for him, or the homeowners to be sure.

Consequently, by the time Mike from Compass Heating and Air got involved, we had pretty much already settled on using multiple heads. Although it was nice to hear the same consistent message from Greg, Isaac, and Mike in this regard.

In the end, we decided to delete the head in the basement, instead going with three separate heads on the main floor — the largest in the kitchen/family room, and then the other two would go in our bedrooms.

Here are the specs for our system:

Hyper-Heat Compressor (30,000 Btu)

MSZ-FH15NA  (kitchen/family room)

MSZ-FH06NA  (master bedroom)

MSZ-FH06NA  (2nd BR)

head in mbr w: section of drywall
Master bedroom Mitsubishi head and Zehnder supply, both covered to protect against construction debris.

Having the Zehnder supply diffusers on the same wall and near the head of the Mitsubishi has been working well for us. As far as we can tell, there are no discernible issues with this arrangement. By way of comparison, the Mitsubishi head and Zehnder supply diffuser are on separate walls in my daughter’s bedroom — in effect, they’re pushing air towards the center of the room from walls that are perpendicular to one another — but we can’t tell any difference in terms of performance, either when heating or cooling.

mbr and family rm erv:heads construction
Facing camera: Family room Zehnder supply diffuser with Mitsubishi head. To the left, and facing MBR: Zehnder supply and lines for MBR Mitsubishi head.

Mike was also really good about communicating the system’s requirements to our electrician and our plumber. It was nice to watch all of them walk through the details together, thereby ensuring there were no problems once it came time to start up the individual heads.

condensate and refrigerant
Components for setting up a ductless mini split: refrigerant lines, electric supply, and a drain for condensate.

Living with a Ductless Mini Split

Having lived with the HVAC system, both the heat pump and ERV, for about a year now, our only real complaint is summer humidity, which I discussed in a previous post here: HVAC (1 of 2): Zehnder ERV

This summer we’re going to try using a dedicated, whole-house dehumidifier, which we think should resolve the issue.

Otherwise, our system has been trouble-free.

In winter, the heads do make some noise, tending to ‘crack’ or ‘pop’, especially when first turning on, or when they come out of defrost mode. Although I’ve read complaints about this online, it’s never really bothered us. I remember how loud our conventional gas-fired furnace was in our last house, especially when it first turned on, so I think it’s important to remember the level of certain sounds in their appropriate context.

Also, this ‘crack’ or ‘pop’ sound is, I suspect, louder than it otherwise would be say in a conventionally built home, since Passive Houses are known to be significantly quieter because of all the air sealing and, in particular, all of the insulation surrounding the structure.

There’s also a noticeable humming sound when the compressor is going through a defrost cycle (especially noticeable at night when the house is otherwise quiet). The heads also temporarily send out cooler air during this defrost cycle, but the cycle is short enough that it hasn’t posed any real comfort issue for us.

heat pump being installed on pad
Setting up the compressor outside.

Regarding interior noise generally, the same holds true even for our refrigerator in the kitchen. We virtually never noticed the fridge in our last house when it was cycling, but in our Passive House it’s arguably the loudest, most consistent noise in the house, especially at night, or if quietly sitting and reading. Again, it took some getting used to, but not really that big of a deal.

In other words, having blocked out, or at least muffled, most of the noise from outdoors (due to extensive air sealing and extensive insulation), any noise indoors becomes much more noticeable and pronounced. The Rockwool we installed between bedrooms-bathrooms, and the kitchen-utility room for sound attenuation definitely helps in this regard (more on this in a later post).

ext line set fully sealed
Line set for the heat pump system exiting the structure after being air sealed.

Just how quiet is a Passive House? Well, one example would be the train tracks that are just a couple of blocks away: When the windows are closed the noise from a passing train is mostly cancelled out — as opposed to when the windows are open, and the train, in contrast, sounds like it’s thundering through our next door neighbor’s yard.

pvc tied down w: duct seal
Interior view of the line set exiting the house.

As far as extreme cold outdoor temperatures are concerned, the system experienced a real test with our recent Polar Vortex weather. Mike was nice enough to check in with us the day before it started just to remind me that the system could shut down if temperatures fell below -18° F, which is what our local weather forecast was predicting.

In fact, this proved entirely accurate. As temperatures eventually fell to -24° F overnight, the system was, in fact, off for a few hours (the Mitsubishi shuts off to protect itself).

With the Zehnder ERV already set to LOW, and using just a couple of small space heaters (one in each bedroom — roughly equivalent to running 2 hair dryers simultaneously), it was easy to get the interior temperatures back up to 68-70° F in less than an hour (from a measured low of 61° F when we first woke up), at which point we turned off the space heaters.

And it was just under 2 hours before the temperatures rose enough outdoors for the heat pump to turn back on. On the second day, the system again turned off, but the interruption was even shorter this time, so we didn’t even bother to turn on the space heaters.

On both days the sun was shining, which definitely helped as light poured in through our south-facing windows, mainly in the kitchen and family room. Even with no additional heat, either from the heat pump or the two small space heaters, the kitchen remained a comfortable 70° F throughout that first day, regardless of the temperature outside.

In the summer, when we have the AC running, we just set the desired temperature on the remotes and largely forget about the system. The three heads together, even in each individual space, have no problem keeping the house and individual rooms cool enough. In this case, it no doubt helps that we have a substantial overhang on the southern portion of our roof, mostly denying the sun an entry point into the home during the hottest days of the year (and the Suntuitive glass on our west-facing windows takes care of afternoon summer sun).

conduit for heat pump thru zip
Conduit for the heat pump exiting the house and air sealed with Roflex/Tescon Vana tape and gasket.

You can see more detailed info regarding air sealing penetrations through the Zip sheathing here: WRB: Zip Sheathing

refrigerant condensate next to beam
Clean, neat lines for the heat pump.

Single or Multiple Heads?

As far as using a single head to try and heat and cool the entire first floor, in our case about 1500 sq. ft., I can only say that I’m glad we chose to use multiple heads. This really hit home as I was completing interior finishes. For instance, there were times when only the head in the family room/kitchen area was running. When you walked into the bedrooms you could definitely feel the temperature difference since those heads had been turned off (roughly a 5-10° difference). As Greg, Isaac, and Mike — to their credit — were all quick to point out, for some homeowners this temperature swing would be acceptable, even something that could be calmly ignored, while for other homeowners it might well be a heartbreaking and deeply frustrating realization.

Depending on how sensitive someone is to these temperature differences, it could  prove a devastating disappointment if the homeowner is expecting uniform consistency throughout their home. Also, since much of the selling point of Passive House techniques is, in the end, occupant comfort, and not just reduced energy consumption, moving from a comfortable kitchen, for example, to a bedroom that some would find outright chilly, might induce some homeowners to ponder: ‘What was the point of all that air sealing and insulation if I’m still cold in the wintertime and hot in the summer?’ If they hadn’t been warned beforehand, like we were, it would be difficult to argue with their reasoning.

Obviously it’s only our opinion, but if it’s at all possible to fit it into the budget, by all means utilize more than one distribution head. Even if you yourself never feel compelled to turn on any of the other heads in a multi-zone system, a spouse, one of your kids, or a guest probably will want to have the option at some point.

cu beam w: zehnder and hp
Zehnder ComfoTubes and various lines for the heat pump as they enter the basement from the MBR and the family room.

In addition, I would also guess that when going to sell the house multiple heads would be significantly easier to sell to a potential buyer (who wouldn’t appreciate customized HVAC in specific rooms?) rather than trying to prove that a single head is sufficient for an entire home, no matter how small or well-designed. Thoughts worth considering before committing to a specific HVAC system.

north facade w: siding
Compressor with finished charred siding and decorative gravel-cobblestone border.

Also worth noting, utilizing the Q&A section of the Green Building Advisor website is an excellent resource for exploring options before committing to a final HVAC set-up. It’s an excellent way to hear from designers and builders who have experience with multiple ‘green’ projects, not to mention actual homeowners who live in high-performance homes and experience these HVAC systems in the real world, as opposed to just data points put into a proposed energy model (incorrect inputs, along with actual occupant behavior are just two ways a potential system could end up being profoundly inappropriate).

This kind of feedback — before construction begins — is undeniably priceless. In fact, I regret not asking more questions on GBA as they came up during the design and construction phases of our build since it is such a valuable resource of useful information.

compressor in snow
View of the same area after our recent Polar Vortex (snowfall, then below-zero temps).

The one real risk we took with our HVAC set-up was foregoing any direct conditioning in the basement, either heat or AC. In the summer, no matter how high the temperatures outdoors, the basement stays within 5 degrees of the upstairs temperatures and humidity, so no comfort issues in this regard have presented themselves. In the winter, however, the temperature remains in the 59-61° range, with almost identical humidity readings as the main floor.

ice under unit
Some ice build-up, but almost all of it on the concrete pad below, not on the compressor itself.

Most of the time this isn’t a problem for us, since we’re either working out (the slight chill gets you moving and keeps you moving), or else we’re doing arts and crafts projects, or reading on a couch under a blanket. The only time the chill gets annoying is when sitting at the computer for an extended period of time, so we may try using a plug-in space heater in the office next winter (although the challenge will be to find one that’s reasonably energy-efficient while also remaining effective).

little ice build-up
Close-up, showing very little ice present on the compressor itself.

Mitsubishi Wall-mounted Heads: Beauty or Beast

I’ve read that some interior designers, and even some homeowners, have expressed aesthetic concerns about the distribution heads. If you go on design-oriented websites like Houzz you can come across some really strong negative opinions on the topic.

family rm:kitchen hp head and zehnder

For us, they’ve never been a problem. Much like the Suntuitive glass on our west-facing windows, or even a dark or bright color on an interior accent wall, after a few days, like anything else, you just get used to it. I never found them to be ugly in the first place though.

MBR w: hp head and zehnder

I also grew up with hydronic metal baseboards for heat, while in apartments and our first home we had the typical floor supply and wall return grilles for a gas furnace — point being, the details of any HVAC system are never completely absent from any living space. There’s always something that shows up visually and, typically, that needs to be cleaned at some point.

In addition, the Zehnder ERV and the Mitsubishi heat pumps meant we didn’t have to utilize any framed soffits or duct chases (at least in the case of our specific floor plan) in order to hide bulky runs of traditional metal ductwork, typical in most homes when using a normal furnace. Unless designed with great care, these tend to be obtrusive, taking up premium ceiling, wall, or floor space. And if randomly placed simply for the convenience of the HVAC contractor, they can be downright ugly.

In other words, it doesn’t really matter if you’re building conventionally or if you’re building a Passive House, all the details of an HVAC system — whether it’s individual components, or even how these components will be placed inside a structure — should be carefully thought through (again, ideally before construction begins) to address any performance or aesthetic concerns.

Controlling and Adjusting the System

As far as the remote controls for the individual heads, we haven’t had any issues.

heat pump remote closed

For the most part, we set them to either heat or AC (roughly 70° and 75° respectively), and then forget about them.

heat pump remote open

To the extent I’ve looked through the manual, these seem straightforward, but again we haven’t really needed to do much in this regard. And when the weather is pleasant outdoors, we take every opportunity to turn off the system completely and then open windows.

Mike also explained the system could be combined with a Kumo cloud set-up, but we’ve been happy with just the hand-held remotes so far.

Routine Maintenance

And much like with the Zehnder ERV, I try to check the filters for the individual heads at least once a month (more like once a week when I was still doing interior finishes). Just as it takes much longer for the Zehnder filters to get dirty now that construction is over, the same has proven true for the blue filters in the Mitsubishi heads. It seems like about once a month is sufficient to keep up with the dust in the house.

Overall, we’ve been very happy with our HVAC set-up, including the Zehnder ERV and our Mitsubishi ductless mini split. As long as the units don’t have any durability issues, we should be happy with these systems for many years to come.

HVAC Part 1: Zehnder ERV

9

DIY Installation

Building with Passive House principles in mind, we knew that, in addition to maintaining a tight building envelope, and incorporating substantial amounts of insulation around the structure, we also needed to install continuous mechanical ventilation in order to have adequate levels of fresh air, not to mention the ability to expel stale air.

We also needed our system, either an HRV or an ERV, to be highly efficient, meaning it could hold onto some of the heat in the conditioned air even as it introduced fresh and, oftentimes, cold air by means of heat exchange as the two streams of air (fresh and stale) passed by one another inside the main unit (without actually mixing together).

After researching the many options, we ended up going with Zehnder’s ERV, in our case, the ComfoAir 350 (the various Zehnder units are based on overall cfm demand of the structure).

We only considered two other brands for our mechanical ventilation (HRV vs. ERV):

UltimateAire

and

Renewaire

In all the research I did prior to construction, these three brands showed up the most in the projects I read about.

Here’s a good debate on the Green Building Advisor website discussing brand options: ERV Choices

Another interesting option would be the CERV system. Because they’re a smaller, newer company, we didn’t feel comfortable pursuing it, but it does look like a viable option worth considering if building a Passive House or Pretty Good House.

I was also familiar with Panasonic units, but I had always read that they weren’t efficient enough in terms of the heat exchange function (or heat recovery) to seriously consider using it in a Passive House or a Pretty Good House in a predominantly cold climate region like ours, here in the Chicago area.

Our Zehnder ComfoAir 350 is said to be 84% efficient in terms of heat recovery (the same principle applies in summer, only working in reverse, when you’re trying to hold onto cooled, conditioned air). Based on what I read during the design phase, the consensus seemed to be that, although more expensive, the Zehnder has a strong track record of performance and durability.

The Zehnder also came with its own ductwork, which we knew would simplify installation, allowing us to do it ourselves, rather than hire someone else to come in and run more conventional ductwork through the house (conventional ductwork would’ve taken up a lot more space as well). Even though the unit itself was more expensive, we thought we could offset some of the total cost for a ventilation system by installing the Zehnder ourselves, thereby saving some money on labor costs.

As far as the ERV/HRV debate for Northern US states, we decided to opt for the ERV because it was supposed to help us hold onto some humidity in winter months, especially important when most structures in the Chicago area are exceedingly dry for most of the winter (and our winters are long). Although I read repeatedly during the design stage that ERV’s can also help control summer outdoor humidity entering the house, this has not been our experience at all. In fact, the ERV seems pretty useless in this regard (more on this below).

The system quote we received was easy to understand, and Zehnder was nice enough to essentially design the system, both in terms of layout (i.e., where we should put all the supply and exhaust points), along with the quantity, or cfm’s, of air for each point. In the end, after commissioning the unit, the system should be balanced, meaning the unit should be bringing in as much fresh outdoor air as it is expelling stale indoor air.

As far as Zehnder units being DIY friendly in terms of installation, in our opinion, this is highly debatable since the installation manual is far from comprehensive. Our installation manual ended at physically installing the main unit on the wall. Not very helpful.

Without a detailed installation manual showing step-by-step how all the individual pieces fit together, you end up with a pile of what initially seems like random parts.

zehnder pile of parts
Everything we need to install our Zehnder ERV. Most of the smaller components are still in the many cardboard boxes off to the right.

This was incredibly frustrating, especially since Zehnder units are purchased at a premium when compared to other competitive brands, and with the expectation of durability and design precision. It never occurred to me to ask before purchasing the unit for an installation manual, since it seemed a fair assumption that no one would sell a premium product without detailed instructions on how to put it together.

We were only able to proceed because of numerous online videos, googling Zehnder unit photos, and by staring at and experimenting with the various parts to try and figure out how it all was supposed to come together. It was an unnecessary and torturous puzzle that shouldn’t have needed solving, and it wasted hours of my life that I’ll never get back. If you do an internet search and type in: “google review Zehnder America” the experience Sean Hoppes had with his installation wasn’t all that different from ours.

Looking on the current Zehnder website (February, 2019), I can’t find a more detailed set of instructions, either written or in a video format, which is disappointing. This seems like a pretty glaring oversight on Zehnder’s part, and one that should be remedied immediately.

Having lived with the unit for almost a year now, overall we’re happy with its performance, and we feel like we could install one fairly easily now that we’ve gone through the entire process, so it’s a shame we can’t say only nice things about the product simply because the installation manual was so limited or, more to the point, non-existent.

With each video and each photo, it was possible to glean one more crucial nugget of information, which took hours, whereas a detailed written manual or a step-by-step video would’ve made the process straightforward, and by comparison, frustration-free.

The videos below were especially helpful, but, nevertheless, they still leave out quite a bit of pertinent information necessary for any first-time installer (especially regarding all the parts that need to be installed on top of the main unit):

Unless there are no DIYers in Europe installing these units, and this is the expectation Zehnder has for its units both for overseas and here in the US, not having a comprehensive installation manual makes no sense. I’m not sure how even a licensed and competent HVAC installer would fare much better without direct experience installing the units. My guess is they would be searching online for missing info much like we did.

Once we got the main unit installed on the wall, and we figured out how all the parts fit together on top of the unit, by the time we got to installing the small, white 3″ ComfoTubes and the large, gray ComfoPipe, the process became much easier.

main unit attached to basement wall
Mounting the main unit to the basement foundation wall with Tapcon concrete screws.

In regards to the gray ComfoPipe for the main fresh air supply and the main exhaust, both of which pass through the wall assembly, we found it more effective to put individual sections together on the floor, and, once fully connected, we marked the points at which the pipes met with a permanent marker.

marking comfopipe w: sharpie
Marking sections of connected ComfoPipe with a Sharpie while they’re on the floor ensures a tight fit once a connection has been made off the floor.

If you try to piece the tubes together one piece at a time in mid-air it’s much harder to gauge when the pieces are actually tightly put together. With each connection point of pipe clearly marked with a Sharpie, it gives you an obvious goal to shoot for once you have the pipe almost in its final position. More to the point, it’s obvious when sections of pipe get out of alignment, or the connection isn’t nearly tight enough — it’s much more difficult to accurately gauge if only going by “feel” once the sections of ComfoPipe are off the floor.

drilling hole for Zehnder exhaust
Making initial cut in the Zip sheathing.

Using a piece of ComfoPipe, we outlined on the interior side of our Zip sheathing exactly where we wanted the pipe to end up (trying to get as close to center as possible — makes air sealing around any penetration much easier). After a hole was cut with a 3″ hole saw, we cut out the rest of the hole using a jigsaw.

hole in Zip for heat pump pvc
Hole cut and ready for the ComfoPipe.
hole set-up for comfopipe
Hole made in our Zip sheathing, ready for the ComfoPipe from outside to make a connection with the section inside.
ext - comfo pipe going thru zip into basement
Ready to push the ComfoPipe into the house from outside to make the connection inside.
Zehnder chipmunk's back
Chipmunks are back.

Once we started using the Sharpie, it was relatively easy to get all the ComfoPipe installed and air sealed around the Zip sheathing.

comfo pipe thru zip
Making the connection between inside and outside.
setting up comfo pipe
Adding a Roflex gasket to make air sealing much easier.
comfo pipe sealed int.
ComfoPipe air sealed on the interior side with Roflex gasket and Tescon Vana.
close up comfopipe sealed
Close-up of the ComfoPipe air sealed at the Zip sheathing.
installing comfo pipe next to main unit
Finishing up the last sections of ComfoPipe as they leave the main unit.

Following the directions, we kept the ComfoPipe exit points for supply and exhaust more than 10′ apart outside, where they enter and exit the structure, in order to avoid any possibility of the two air streams mixing, which would undermine the effectiveness of the system.

comfopipe ext sealed and covered
Repeating the same air sealing process on the exterior for the ComfoPipe, adding black garbage bags over the opening with rubber bands to keep out dust, dirt, birds, and any critters that might otherwise try to enter the structure during construction.

On the outside, we made sure to extend the ComfoPipe out farther than we needed, giving us some leeway once insulation and siding were installed over the Zip sheathing. This allowed us to cut the ComfoPipe back to the proper depth before installing the permanent covers supplied by Zehnder.

comfo pipe ext close up sealed
Close-up of ComfoPipe as it exits the structure (before insulation, furring strips, siding, and its final cover).

As far as the white tubing is concerned, we really enjoyed how easy it was to put the 3″ ComfoTubes together.

During the design phase, and even after we brought the Zehnder unit to the job site, we always intended to place the diffusers for supply and exhaust points on ceilings. But after really looking at all the cuts in our ceiling service chase that would be required to make this happen, we decided to opt for placing all of them on walls instead.

It proved to be one of the better decisions we made during construction. Not only did we avoid having to make many cuts in our ceiling structure, which would’ve meant a struggle to appropriately map them out around conduit, ceiling lights, and plumbing vents, it had the added benefit of making it much easier to do ongoing maintenance at the diffusers, mainly checking on and cleaning filters, once we moved in.

cone diffuser filter
Cone shaped filter for exhaust diffusers (bathrooms, kitchen, laundry room, and basement in our case).

In fact, during commissioning, our Zehnder rep told me they have issues with homeowners not keeping their exhaust diffuser filters properly cleaned, effectively undermining the efficiency and overall performance of the units. This is understandable if the diffusers are on ceilings, whether at 8′ or 9′. It would be easy to forget about them, or even if you did remember, one can understand the reluctance to drag out a 6′ step ladder every time they needed to be cleaned. We were also told that placement of the diffusers is extremely flexible — almost anywhere can work (check with Zehnder directly just to make sure your proposed placement will work).

inside diffuser filter
Diffuser filter in bathroom after about a month. Once all the construction dust settled down from completing interior finishes, these filters don’t get dirty nearly as quickly as they once did — in other words, this isn’t bad at all.

By keeping them around 7′ off the finished floor, it’s easy for me to check and clean the exhaust diffuser filters on a regular basis (1-2) times a month. I always have 2 sets of filters, so it’s easy to remove the dirty ones, put in clean ones, and then rinse and dry out the dirty ones.

Once we decided to go through walls (both 2×6 and 2×4 framed walls), it was just a matter of deciding where in each wall we wanted the diffusers to be placed, and then cutting the corresponding hole through the wall’s bottom plate and the subfloor — being careful to check, and re-check, in the basement for any floor joists, plumbing, or electric conduit that might be in the way.

For bathrooms we placed the diffusers between showers and toilets, slightly cheating towards the showers to ensure maximum moisture removal.

changa drilling for tubes
Apparently cutting the holes through the floor looked like fun since my wife was happy to take over this chore for me. The DeWalt we were using worked great until it crapped out on us a couple of holes short of finishing. We definitely noticed a difference going back to a normal drill and hole saw set-up.

At the unit itself, Zehnder supplied us with blue (fresh air) and red (stale air) tags, to mark each ComfoTube as it leaves or returns to the main unit. This should make any potential maintenance or repair issues in the future easier to resolve, as well as helping to avoid confusion as you set in place each pipe at a diffuser.

first few return tubes are in
Attaching the white ComfoTubes to the main unit, carefully labeling each pipe for future reference.
main unit w: exhaust tubing installed
ComfoTubes being installed at the main unit.
top of silencers #2
Close-up of the top of the main unit, as ComfoTubes are being installed.
Sydney helping us
Sydney, one of our former Excel students, was nice enough to stop by and help us pull the ComfoTubes from the basement up to the first floor.