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Passive House + Net Zero Energy + Permaculture Yard

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

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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…

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.

“Yet an investigation of the process by which buildings rise reveals… a pedestrian combination of low ambition, ignorance, greed and accident… the work of a few people neither particularly sinful nor malevolent… yet, in a few weeks, they can put in motion plans which will substantially ruin a landscape for 300 years or more… banal thinking… [can] leave wounds which will be visible from outer space. Bad architecture is a frozen mistake writ large… While mourning the number of missed opportunities, we have no reason to abandon a belief in the ever-present possibility of moulding circumstances for the better… There are few harsher indictments against architecture than the sadness we feel at the arrival of bulldozers, for our grief is in almost all cases fuelled more by a distaste for what is to be built than by any hatred of the idea of development itself.”

— Alain de Botton, The Architecture of Happiness

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 suburbia… children of the affluent are raised with the idea that they are in the midst of a legitimate American dream… most failures within the the suburban landscape are due to economic success… The suburban dream rests on the social and environmental nightmare that haunts the inner cities and the harrowed countryside… What about the fact that most suburban or urban kids want to work in a meaningful way but cannot do so?… We teach boredom to our suburban children in countless ways. Children need reality, not virtual reality. Children need to understand our source for survival, whether it is wood for a stove or food for their bellies… What better place to teach the essentials of agriculture and forestry than in the suburbs, where most people live?”

— Wes Jackson, Consulting the Genius of the Place

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.

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

Attic Access Hatch (Air Sealing #7 )

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Our attic is designed mainly to hold our blown-in insulation (a future post will go over the details), as opposed to a place for running HVAC equipment, conduit for electric, or as a potential area for carving out additional storage space.

Nevertheless, in order to have access to our attic for future maintenance or repairs, I installed a well-insulated attic hatch in our master bedroom closet ceiling.

Following Passive House and Pretty Good House principles required trying to protect the thermal envelope, even in this relatively small area, in order to avoid what can be a notorious point of air leakage and heat loss (i.e., the stack effect).

There were two main products I considered using for this:

Battic Door (R-50 / without ladder)

They also have a product that allows for a built-in ladder for easier access to the attic (you won’t need to drag your ladder in from the garage) while also maintaining a high R-value:

Battic Stair Cover

The other product I considered using was from ESS Energy Products:

Energy Guardian Push Up Hatch Cover

We ended up going with the Battic product, which I purchased through the Home Depot website (this saved me a trip to the store since it was delivered to site).

Some other products that I’m aware of include:

475 High Performance Building Supply used to sell a Passive House certified version with a fold-down ladder included, but I don’t currently see it listed on their website:

WIPPRO Klimatec 160

Or this product that also incorporates a ladder is available from Conservation Technology:

Attic Ladder

Because the Energy Guardian hatch is made out of rigid foam, I thought the Battic door was the better choice since it seemed like it would be a little sturdier and more durable. To be honest, once the product arrived and I unpacked it, I realized it was something I, or anyone with basic carpentry skills, could put together themselves (assuming you have the time).

Following the directions, I cut an X in the Intello on the ceiling between two roof trusses (and our 2×6 service core below each truss) in order to establish the opening for the Battic frame.

I folded the cut edges of Intello up into the attic for the two long sides of the Battic frame. For the two shorter sides of the Battic frame it was easier for air sealing to push the Intello down into the living area.

At this point I was able to screw the Battic frame into place.

looking up into battic attic hatch
Battic frame initially installed between roof trusses and 2×6 service core.

Once in place, I used a mix of Contega HF Sealant and Tescon Vana tape to air seal the Intello to the Battic frame.

battic - taped sealed to intello
Air sealing the Intello to the Battic frame (short side between trusses).
tescon vana air sealed battic w: HF behind Intello
Another view of the Intello sealed to the Battic frame.
looking down at air sealed battic from attic
View of the installed Battic frame from the attic.
attic access air sealed - attic side
Air sealing the connections between the Intello, the Battic frame, and the roof trusses in the attic.
air sealed corner of battic
Using HF Sealant to make the connections as air tight as possible.

Once the outside perimeter of the Battic frame had been air sealed to the Intello, the only place left for air infiltration was where the lid would meet the frame of the Battic hatch once it was installed (more on this later when I discuss my first blower door test).

There was some additional framing required, but it was just a couple of “headers” between the roof trusses to add structural integrity to the two shorter sides of the Battic frame.

attic access from below
Battic frame with additional 2×6’s on one of the short sides.

Since we were using a significant amount of blown-in insulation in the attic, it made it necessary to build up the sides of the Battic frame in the attic with some plywood to get the top of the opening above where the insulation would eventually stop.

Here’s another view of the 3 sides of plywood installed:

attic access looking down - directly

The fourth and final side of plywood was installed just prior to blowing in the insulation — in the interim this made getting in and out of the attic much easier.

After a couple of practice attempts, it quickly became apparent that raising and removing the lid once in place, and fighting to get it back down into the master bedroom closet, wasn’t worth the trouble. Instead, I built a small bench in the attic next to the Battic frame so I could push the lid up above the level of blown-in insulation, this way it could have somewhere to safely sit while dealing with any issue in the attic.

bench for attic access lid
Battic lid resting on the bench.

It’s very easy to grab the lid off the bench and bring it back down into position while slowly walking down the ladder in the master bedroom closet to make the final connection/seal.

Although the installation process was fairly straightforward and headache free for the Battic product, if I had it to do over, I think I would have the attic access point on the exterior of the structure, for example, on the gable end of the house in the backyard.

GBA – gable access to attic
Custom Gable Vents
AZdiy

Putting the access point above the air barrier would make meticulously air sealing the entry point for the attic less important, so keeping water out of the attic would be the main goal. An additional plywood buck would’ve been necessary, replicating what I did for our windows and doors (more on this later), but I think it still would’ve been the better option overall.

Putting the attic access on the exterior of the house would also mean avoiding an ugly hole somewhere in our drywalled ceiling. No matter how nicely trimmed out, these attic access points on the interior of a home never look right to me. We’ve tried to hide ours as much as possible by sticking it in our master bedroom closet, which has worked out well, but not having one at all on the interior of the house would make for a cleaner, better solution in my opinion.

If granted a do-over, I would also add a cat walk in the attic through the roof trusses. This would make getting to any point in the attic much easier to navigate. It would also help to avoid disturbing the blown-in insulation too much.

And here’s a photo of the bench in the attic, next to the opening for the Battic attic hatch, after the blown-in insulation was installed:

bench surrounded by cellulose
Bench for the Battic hatch lid.

WRB: Zip Sheathing (Air Sealing #6 )

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Sealing the Seams and Penetrations in Zip Sheathing

Note: This post will concentrate on the Zip sheathing itself, as it relates to seams and penetrations. I’ll address how I sealed around openings for windows and doors, along with our attic access hatch through the Intello on the ceiling in separate, future blog posts.

We used Zip sheathing as our WRB (weather resistant barrier — sometimes it’s referred to as a water-resistant barrier) based largely on Hammer and Hand projects:

Also, for years I’d seen it used on various jobs featured in Fine Homebuilding Magazine.

As the 7/16″ Zip sheathing went up, I taped most of the seams with Pro Clima’s  3″ Tescon Vana tape (available at 475 HPBS), but also their Contega tape (6″ wide), which I used mainly for outside corners and larger seams in the Zip (mainly where the horizontal seam in the Zip transitioned from the exterior walls of 2×6 framing to the roof trusses — shown in a photo later in this post).

My wife and daughter also cut up the Tescon Vana tape into small pieces in order to cover all the nail and screw holes in the Zip sheathing.

beast and eduardo taping nail holes
The Beast and Eduardo team up to tape the nail and screw holes on the lower sections of Zip sheathing around the house.

The nail holes were initially sealed with HF Sealant, also available from 475 HPBS, thus giving them double coverage — this was discussed earlier, here:

Framing (Air Sealing #2)
north side house garage gap long view
Northeast corner of the house where it meets the garage.

Our decision to use the Zip sheathing was also discussed earlier, here:

Wall Assembly

And here’s a good video discussing the Zip sheathing and its benefits (and its place in the evolution of building science):

If I had it to do over, I think I might be tempted to use 1/2″ exterior grade plywood as my sheathing (there are any number of WRB options these days). This would be sealed on the exterior side with either a liquid membrane, like Prosoco’s Cat 5, or a peel-n-stick tape like Henry’s Blue Skinor even another 475 HPBS product Solitex Mento 1000.

The Zip sheathing works, and the exterior green skin held up nicely during construction, even as it sat exposed for nearly 10 months after we fired our GC’s and struggled to keep the project moving forward. Nevertheless, it is little more than glorified OSB, which comes with certain inherent weaknesses.

Matt Risinger does an excellent job of delineating the cost/benefits of using either OSB or CDX plywood as a sheathing material:

house-garage-gap-for-4%22-roxul
Garage (at left) house (at right) connection. Gap will eventually be filled with 4″ of Roxul Comfortboard 80.
garage-house-gap-2
Closer view of this same garage – house connection. Flashing will cover the bottom of the Zip and then carry over the top of the Roxul that covers the foundation.
north-side-seams-taped
View of the north side of the house as Tescon Vana tape air seals the nail holes and the seams in the Zip sheathing.

View of the West facade with Tescon Vana tape, along with the black Contega tape at larger seams (e.g. where the walls meet the roof trusses) and outside corners.

west side being taped
West facade as taping proceeds.
taping north side before mechanicals : windows
Northwest corner of the house, transitioning from the Tescon Vana to the black Contega tape at the corner.
finishing up seams on west facade
Finishing up some of the final seams in the Zip on the West facade.

Once the Zip was fully installed, it was readily apparent that some of the seams, especially near the base of the first floor where a horizontal seam ran around the entire structure, would need to be tightened up.

Here’s a view looking down on one of these areas where the Zip sheathing did not sit flat against the framing members:

down Zip - out of alignment before 1x4's
Horizontal seam in Zip sheathing refusing to lie flat against the 2×6 framing members.

Using a 1×4 in each stud bay, I was able to pull the seam in the Zip sheathing together. It wasn’t always perfect, but the difference was visibly significant and in most areas well worth the effort.

Placing a 1×4 into position over the seam in the Zip, I would drive a couple of screws towards the exterior.

1x4 in study bay before HF
1×4 used to pull an unruly seam in the Zip sheathing together.
screw thru zip for 1x4 in stud bay
Screw from the interior poking outside as it initially gets the 1×4 in place.

Once securely attached from the interior, I went outside and drove several screws into the Zip, both above and below the seam in the Zip, to pull the seam tight to the 1×4. At that point, I could go back inside and remove the two screws that were driven towards the exterior.

In addition to air sealing the exterior side of the Zip sheathing, I also invested some time in air sealing the interior side of the Zip as well. Below is a long view of several stud bays with 1×4’s installed, but before air sealing gaps around the 1×4’s and lower areas of the stud bays with HF Sealant.

stud bays w: 1x4's, before HF

Long view after applying the HF Sealant:

ceiling walls - HF Sealant

Close-up of the interior side of the Zip sheathing meeting a 2×6 framing member in a stud bay after applying a thick bead of HF Sealant:

thick bead HF sealant in stud bay

Close-up of lower area of a stud bay after air sealing with the HF Sealant (it transitions from a light to darker green as it dries):

stud bay w: 1x4 and HF sealant
1×4 installed and HF sealant applied to all gaps and screw/nail holes in the stud bay.

I held off on using the HF Sealant at the wall sill plate/subfloor connection until just prior to installing the Intello on the walls since this area constantly attracts dirt and debris.

Sealing on the interior side with HF Sealant, even between vertical framing members, means that even if there are any weaknesses in either the Zip sheathing or the Tescon Vana tape at these points, air won’t find an easy way in, since it will be blocked from the interior side as well (there won’t be a difference in air pressure to help the outdoor air make its way indoors).

This kind of redundancy in air sealing should give the house long-term protection against air leaks, thereby aiding the long-term durability of the structure, as well as making it a much more comfortable environment to live in.

interior walls sealed w: HF sealant
Using HF Sealant between vertical framing members.

I also spent some time on the roof trusses, sealing around nails, the top plates of the exterior walls, and the many Zip-framing member connections in what will eventually be the attic.

sitting on roof trusses sealing
Sealing around fasteners and framing in the attic with HF Sealant.

This had less to do with air sealing and more to do with preventing any potential water intrusion since this area is technically above our ceiling air barrier (the Intello), which is detailed here:

Ceiling Details (Air Sealing #4)

Inventory of Penetrations through the Zip Air Barrier

I made a mock wall assembly before construction began, which I discussed here:

Wall Assembly

This proved helpful when explaining to the various subs how to help me protect the air barrier — especially when it came time to drill holes through the Zip sheathing. Of particular importance was making holes closer to the center of a stud bay, as opposed to hugging a corner or side of one of the 2×6 framing members. A hole cut too close to a stud or a roof truss is much harder to properly air seal.

bad-good-mock-wall-assembly-for-penetrations
Interior side of our mock wall assembly showing how all penetrations through the Zip should be in the middle of our framing members. Our original plumber was the only trade that managed to screw this up (it’s no coincidence that he was also the only sub that we had to fire).

In effect, any time a sub had to make a penetration through the air barrier we discussed the details, and once the cut was made I immediately air sealed the penetration both on the exterior and interior side.

By sealing each hole in the Zip on both sides, again I hope it ensures the long-term durability of the overall structure. The main argument for this strategy assumes the exterior side of the sheathing will face more extreme temperatures, and fluctuations in humidity, and presumably even wind-drive rain if/when it gets past the siding and 4″ of Roxul insulation, putting it at greater risk of failure (especially in the long term). By taking the time to air seal the interior side, it just gives the overall air barrier, and therefore the structure, a better chance at avoiding air and water intrusion (that’s the goal anyway).

For air sealing I used a mix of tapes, HF sealant (later even some Prosoco products), EPDM Roflex gaskets, and duct seal.

The penetrations for electric service were my first go at using the Roflex gaskets:

John & Donny installing meter
John and Danny installing the electric meter.

The smaller diameter Roflex gasket comes with its own Tescon Vana tape, which makes installation straightforward.

close up meter thru Zip w: TVana gaskets
Electric meter with Tescon Vana – Roflex gaskets installed.
meter - hole, t. vana prior to appl.

Exterior view of electric Meter air sealed with gaskets and Tescon Vana tape:

electric meter close up gasket : t. vana

Once sealed on the exterior side, I went inside to seal the penetrations for a second time:

meter to panel - interior
Air sealing the electric meter on the interior side.

It was a big moment when the electric panel went in:

main panel in - progress
The house is ready for power.

The installation of our solar panels required air sealing two penetrations — one through the Intello on the ceiling on the inside of the structure, along with one exterior penetration through the Zip:

Details regarding the installation of our Solar array can be found here:

Solar on the Roof
corrected solar on:off
Solar disconnect (on/off) with its Tescon Vana gasket.

We also had two frost-free hose bibs, or sill cocks, installed, which also required gaskets on the exterior and interior sides of the Zip sheathing.

hosebib w: gasket
Frost free hose bib with gasket.

One of the big advantages a Roflex gasket has over using a sealant like the green HF Sealant, or Prosoco’s Joint and Seam, is the pipe can be moved in and out even after air sealing, which is especially helpful for installing siding later.

We left the sill cocks loose (unconnected to water supply line inside the house), allowing the siding guys to adjust in and out for a more precise fit of the charred cedar siding.

Below is an example of what conduit through the Zip sheathing looks like before it gets a gasket and some tape:

exterior light conduit before gasket
Penetration for conduit before gasket.

And here’s the conduit after the gasket and some tape:

gasket for exterior light
Conduit after gasket.

Note the extended length of the conduit, anticipating our 4″ of Roxul covering the Zip, 2-layers of furring strips (vertical then horizontal — for vertically oriented siding), and the eventual charred cedar siding.

The photo below shows the penetrations, along with multiple lines of conduit, for our eventual ductless mini-split Mitsubishi heat pump system. The empty hole will be our disconnect for the heat pump. I’ll go into the details of our ductless mini-split system in a future post.

conduit for heat pumps
Penetrations for our Mitsubishi heat pump system.

Same series of conduit pipes after gaskets and being connected to the compressor outside:

heat pump electric w: t. vana before disconnect

In addition to the conduit for electrical hook-up, the Mitsubishi heat pump system required a separate penetration for running the refrigerant lines to the compressor:

hole in Zip for heat pump pvc
Hole cut for the heat pump refrigerant lines.

After discussing it with Mike from Compass Heating and Air, who did our ductless mini-split installation, we decided to use a 4″ section of PVC plumbing pipe as our “conduit” for running the refrigerant lines from the interior of the structure to the outside:

heat pump - pvc pipe in hole for lines
4″ PVC plumbing pipe for the refrigerant lines.

After the PVC was passed through the hole in the Zip, we added a 2×4 underneath it to give it some added stability, along with the usual gasket and tape for air sealing around the PVC pipe:

heat pump - int side - pvc, gasket, 2x4
Before applying Tescon Vana around the Roflex gasket.

Once the refrigerant lines were passed through the PVC pipe, it was clear that some additional air sealing was required.

gaps around pvc lines before duct seal
PVC pipe with refrigerant lines installed.

I filled the gaps around the refrigerant lines from the interior and exterior sides with duct seal. Before stuffing in the duct seal at either end of the PVC pipe, I added bits of Roxul Comfortboard 80 into the pipe to try and give added R-value to the interior of the PVC pipe (hoping to prevent any possible condensation from forming inside the pipe).

duct seal label
A real lifesaver when it comes to air sealing. Readily available at big box stores, or online at Amazon.

Duct seal proved especially helpful at air sealing multiple weak points in the structure —areas that would’ve been difficult or impossible to air seal with just tape, gaskets, or sealants:

heat pump pvc w: duct seal close up interior
Using duct seal to block off air from the interior side.
heat pump pvc w: gasket before t. vana close up
Another view of the PVC pipe with duct seal.
heat pump refrigerant lines - int. leaving basement
The refrigerant lines transitioning from the basement ceiling to the PVC pipe before leaving the structure.

Once the interior was taken care of, I was able to address the exterior side of the PVC pipe:

heat pump lines before tape after duct seal
Exterior view of the PVC pipe with heat pump refrigerant lines exiting the structure. Air sealed with a Roflex gasket and duct seal inside the pipe.

Again, note that the PVC pipe is extended out in preparation for the layers of exterior insulation, furring strips, and siding:

heat pump lines leaving house - sealed
Same area after completing the air sealing with Tescon Vana tape.

And here’s a view of the same area after the siding was installed (I’ll go into the many details regarding the installation of the exterior insulation, furring strips, and siding in a future post):

Heat pump lines w: duct seal and siding
Air sealing for the refrigerant lines complete after the siding is installed.

Additional areas where the duct seal proved to be invaluable:

close up exterior outlet box w: duct seal
Exterior electrical boxes for lights and outlets.

Conduit for the water meter in the basement (only the interior is shown below, but the conduit was air sealed with duct seal on the exterior end as well):

And here’s the same conduit for the water meter as it leaves the house on the first floor:

conduit for water meter sealed w: tape:gasket
Conduit for the water meter, air sealed on both sides of the Zip with the Roflex/Tescon Vana gasket.

I also had to address the disconnect boxes for our solar array and our heat pump. For instance, here’s our solar disconnect box when it’s open:

solar disconnect before removing

And here it is after removing the pull out switch, revealing an air leak:

solar disconnect before duct seal

Close-up of the conduit:

close up solar disconnect before duct seal

An even closer look:

close up penetration in solar box before duct seal

And here it is after being air sealed with the duct seal:

close up solar box after duct seal

I did the same air sealing for the Mitsubishi heat pump disconnect box:

heat pump box before removing

Close-up of the conduit sealed with the duct seal:

close up penetration in heat pump box w: duct seal

During my initial blower door test (more on that later), some air movement around the main panel in the basement was detected, so when the electrician came back we added duct seal to the main pipe entering the house (it had already been sealed from the exterior side with duct seal):

main panel - interior - duct seal
Close-up view of the main panel from the interior where lines first enter the structure.

Besides the penetrations in the Zip sheathing, there were other penetrations through the Intello (our air barrier on the ceiling) that had to be addressed as well. These areas were air sealed with the same set of products as the Zip.

For example, in addition to the conduit for solar through the Intello, we also had to air seal conduit for electric service to the attic (for a light and switch in the attic), in addition to the the penetrations for radon and plumbing waste vents, some of which are shown below:

plumbing vent thru Intello gasket:t. vana
Plumbing waste vent going into the attic.

Another view of this vent pipe after air sealing, this time from below:

sealed plumbing vent from below

Here is one of the vents that our first, incompetent plumber installed too close to one of the 2×6’s used to establish our service core:

plumbing vent installed too close to 2x6
Installed this close to framing makes air sealing the vent needlessly complicated and frustrating.

Here’s the same area after applying the Tescon Vana tape:

plumbing vent too close to 2x6 sealed w: tape

Below is another vent pipe incorrectly installed too close to a 2×6. This one was even more challenging to air seal properly. After the gasket and Tescon Vana, I added the green HF sealant as insurance against air leaks, both for now and in the future.

vent too close w: sealant too

We also had to air seal the penetrations for our Zehnder Comfo-Air 350 ERV ventilation unit. I’ll go into the details of the actual installation later, but here are some photos of the penetrations through the Zip sheathing and how we addressed making them air tight:

ext - comfo pipe going thru zip into basement
First section of Comfo pipe going through the Zip sheathing.
Zehnder tube exiting w: gasket
The gray Zehnder Comfo pipe (for supply air stream) exiting the structure with a Roflex gasket.
Zehnder pipe sealed w: gasket and tape
Closer view of the Comfo pipe air sealed with a gasket and Tescon Vana tape.
close up Zehnder Comfo Pipe w: gasket and t. vana
An even closer view of this same area where pipe meets gasket and tape.

We followed the same process — Roflex gasket and Tescon Vana tape — for the exterior side of the Zehnder Comfo pipe:

ext Zehnder gasket : t. vana
Zehnder Comfo pipe installed, air sealed, and ready for commissioning.

And here’s a picture of both supply and exhaust pipes for the Zehnder:

Zehnder exhaust and supply pipes ext fully sealed
Supply pipe in the background, exhaust in the foreground. The garbage bags keep out weather and animals until after the siding is up and the permanent covers can be installed.

During my initial blower door test some air movement around the sump pit was detected.

sump pit air sealed
Sump pit lid sealed with duct seal, Roflex gasket with Tescon Vana, and the seam between the pit and lid sealed with Prosoco Air Dam.

The sump pump discharge pipe also needed to be air sealed on both sides of the Zip:

sump discharge pipe w: gasket and joint and seam
Sump discharge pipe sealed first with Prosoco Joint and Seam, then a Roflex gasket, before applying Tescon Vana tape around the gasket.

Some air movement around the ejector pit was also detected, so I used duct seal to try and block it.

ejector pit air sealed with duct seal
Ejector pit air sealed with duct seal.

For low voltage — in our case, a cable TV/Internet connection — we found a utility box at Lowe’s (also available at Home Depot and Amazon), and combined it with conduit to transition from the exterior to the interior. The diameter of the conduit is large enough to allow wires for other utilities/services to pass through as well, if necessary, in the future.

cable box
Cable box installed after the siding went up.

An engineer from Comcast-Xfinity visited the site back in the summer, and he gave me the go-ahead for using this box/conduit set-up:

close up exterior of closed cable box
Closer view of the cable box.
cable box ext without cover
The cable wire exiting the house through the conduit, which is air sealed with duct seal.
cable wire int. basement
Cable wire on the interior of the house exiting through the Roxul insulation and Zip sheathing via the conduit and then air sealed from the interior with duct seal.

Even the wire for the doorbell was sealed with a gasket and tape:

doorbell gasket and tape
When the weather warmed up I was able to experiment with the Prosoco R-Guard series of products (note the 3/4″ plywood door buck treated with Joint and Seam and Fast Flash). I’ll go into that more when I discuss prepping for the windows and doors later.
close up of doorbell gasket
A closer view of the doorbell gasket.

Air sealing the penetrations was challenging at times, but also a lot of fun — always keeping in mind the goal of meeting the Passive House standard of 0.6 ACH@50 for our blower door test.

Convinced of the connection between air tightness and the durability of a structure — not to mention the impact air tightness has on heating and cooling loads (i.e. monthly utility bills) —I wanted to see just how air tight I could get the house.

Hopefully this inventory of penetrations will prove helpful to someone in the planning stages of their own “air tight” build. It always helps seeing how other people do things — in particular, the strategies they employ and the specific products they use.

Seeing these real world examples of air sealing around the many penetrations in a structure will hopefully give others the confidence to come up with their own plan of attack for building an airtight structure.

Solar on the Roof

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After deciding to pursue a combination of Passive House and The Pretty Good House concepts, which entail careful planning and attention to air sealing, along with a significant amount of insulation, we knew we could have a shot at Net Zero, or Zero Net Energy (ZNE) — meaning we could potentially produce as much energy as we use by utilizing solar panels on the roof.

To find an installer in our area, we utilized the website Energy Sage. In addition to useful articles and information about solar, they also work with installers who can provide consumers with competitive bids. It didn’t happen overnight, but in about a week or two, we ended up with 3-4 bids before deciding to go with Rethink Electric.

laying out the solar panels pre-install
The guys from Rethink staging the panels on the garage roof.

The System

Based on the suggestions from Energy Sage and Rethink, we ended up going with the following system:

  • 2.915 kW DC System
  • 4,059 kWh of system production
  • 11 Canadian Solar panels
  • 265W Module Enphase M250 (Microinverter)
  • Also includes web-based monitoring of the system’s production

In theory, this system could produce more energy than we use (it’s just my wife, my daughter, and myself who will be living in the house), particularly if we stick to all LED lighting, use Energy Star rated appliances, the heat pump water heater works as advertised, and we’re careful about avoiding using electricity when it’s unnecessary (e.g. turning off lights after leaving a room, or trying to address phantom loads).

Anthony putting self-adhering gasket over solar conduit penetration
Anthony, from Rethink, air sealing the penetration through the Intello, our ceiling air barrier,  with a Tescon Vana – Roflex gasket before sending his 3/4″ conduit into the attic.

Based on other projects I’ve read about, even homes initially built to the ZNE standard sometimes fail, in terms of overall performance, based on actual occupant behavior, so only time will really tell what impact our solar array will have on our utility bills. It looks like worst case scenario would be needing to add 4-6 more panels to get to ZNE or even carbon positive.

conduit for solar in the attic before gasket
Anthony’s conduit entering the attic, sealed with a gasket from below.

Installation by Rethink went really well, and they were happy to work with me on properly air sealing the conduit that runs from the basement at the main panel before going up into the attic, where it eventually terminates on the roof when connected to the panels.

conduit for solar in the attic after gasket
3/4″ conduit sealed for a second time on the attic side of the Intello.
solar mounting system being installed
The guys setting up the racking system for the panels.
close up solar base
Close-up of the base that’s holding the solar panels.
Rethink guys on the roof
Anthony, Dan, and Cherif completing the install on the roof of the house.
close up of solar panels being installed
The low profile racking system has a very sleek look.

Marking another big leap in the progress of the build:

solar panels on roof
The view of our 11 solar panels from our neighbor’s driveway.
solar panels installed on the roof.jpg
Another view of the solar panels installed on the roof.

It was only after the installation that I realized what’s wrong with the following picture:

solar on:off against Zip sheathing #2
My screw up.

I was so worried about getting the air sealing details right on the interior, from the main floor to the attic, I completely forgot to let Anthony know about extending out his disconnect box 6″ to what will be our finished surface (once two layers of Roxul and two layers of 1×4 furring strips, along with cedar siding are installed). The day after they installed, I came walking around the corner of the house, saw this, and literally slapped my forehead (while spitting out a few choice expletives), as I realized my screw up.

Thankfully, Anthony was able to come back out and make the necessary adjustment:

corrected solar on:off

The Cost

Here’s the cost breakdown on our system (if trends continue, a similar system should be less expensive in the future):

$12,519.50  Initial Investment
$(-3,755.85)  Federal Tax Credit (ITC) 30%
$8,763.65  Net Cost of First Year
$(-3,816.00)  Solar Renewable Energy Credits (SREC’s)
$4,947.65  Net Cost After All Incentives

It will be interesting to follow the performance of the solar panels over the course of a calendar year or two, just to find out exactly how well they perform. I’ll come back here and post monthly utility statements, noting output of the panels and our use, to give people a better sense of actual performance — hopefully this will help others in the planning stages of their own project to decide if solar (and how much of it) is right for them.

{January, 2021 Update: For actual energy demand and costs, please check out this post: Our Energy Bills}

Framing (Air Sealing #2)

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Mudsills

In a conventionally built home, mudsills are typically an area of significant air leakage (if you’ve ever seen sill sealer — a thin layer of foam normally used to address this lumber-concrete connection — under an actual mudsill, you can visibly see just how poorly it performs).

In contrast, after reading about various strategies employed to reach the Passive House standard of 0.6 ACH@50 for air tightness, I decided to use the approach developed by architect Steve Baczek specifically for mudsills. There is an excellent article in Fine Homebuilding magazine that describes the details, and there is a companion series of videos available on Green Building Advisor (after the first video, membership is required, but it’s well worth it for this series of videos, as well as all the other information available on GBA).

We didn’t use the layer of poly, or the termite shield, but the remaining details we followed fairly closely. And we did make one product substitution — instead of using the Tremco acoustical sealant, we decided to go with the Contega HF sealant (less messy, lower VOC’s, and skins over and firms up enough to apply the Pro Clima tapes, all while remaining permanently flexible like the Tremco product —  these products are available at foursevenfive.com).

bill-and-phil-setting-up-chalk-lines-for-mudsill
Billy and Phil setting up chalk lines for the mudsills.
nils-running-bead-of-sealant-before-mudsill-goes-down
Nils applying a thick, continuous bead of Contega HF sealant, including around the bolts, before the 2×6 pressure treated sill plate gets installed with a BG65 gasket underneath.
ct-gasket-close-up-on-srap-board
BG65 gasket from Conservation Technology stapled to the bottom of a scrap piece of sill plate.
ct-gasket
BG65 gasket rolled up in the box it shipped in.
Sammy and Billy stapling the BG65 gasket to the sill plates before installation.
mudsill-squeeze-out
Mudsill installed with some squeeze out of the sealant.

Installing the sealant on the mudsill (interior/exterior edges, seams, and bolts/nuts/washers) required some gymnastics:

selfie-by-window-buck
In theory, she’s helping me.
mudsill-with-gasket-and-sealant-garage-from-inside-basement
Mudsill after installation: sealant covering sill plate – BG65 gasket – concrete connection, with seams filled.

Once again, based on Steve Baczek’s design — going from exterior to interior — here is our Mudsill Air Sealing Approach:

  • Bead of sealant on the exterior side of the 2×6/foundation connection
  • BG65 gasket under the sill plate — along with a thick bead of sealant under the gasket and sill plate (including around bolts)
  • Bead of sealant on the interior side of the 2×6/foundation connection
  • And then, finally, a taped connection on the interior side of the 2×6/foundation connection as a last line of defense against air infiltration (which I’ll complete once all the trades go through the interior of the house).

The approach assumes I will make mistakes at certain points with each layer of air sealing, so I’m counting on these layers of redundancy to protect me from myself. Again, this is the first time I’ve ever done this, so the theory is that even if I make a mistake in one area, it’s unlikely that I will make a mistake in exactly the same spot with successive layers of air sealing.

Obviously I’m trying to do my best with each layer, but I like the idea of added layers of protection (a Passive House obsession), especially when accounting for the long-term life of the structure. Even if each layer could be installed perfectly, presumably each layer will fail eventually at different times and in different places (hopefully 50-100 years from now if the accelerated aging studies are accurate), so hopefully these layers of redundancy will help maintain significant air tightness far longer than if I chose to use fewer layers. Plus, I’m enjoying sealing everything up, so I don’t mind the process, which always helps.

For larger gaps (not just for mudsills, but anywhere in the building envelope), roughly 3/8″ inch or larger, I am utilizing backer rod to help fill the gap before applying sealant.

This is what it looks like:

The backer rod (readily available at any hardware store) makes life easier for caulks and sealants — less stress on the connection between materials as the inevitable expansion and contraction occurs in the gap.

Hammer and Hand’s Best Practices Manual has the best explanation for their use that I’ve come across:

“While the humble sealant joint may be uncelebrated, it is vital to building durability and longevity. Proper installation is key to sealant joint integrity and function throughout a life of expansion and compression, wetting and drying, exposure, and temperature fluctuation.

Note: Because sealants are just as good at keeping moisture in as they are in keeping it out, placing a bead of caulk in the wrong location can result in moisture accumulation, mold and rot, envelope failure, and hundreds of thousands of dollars in repair and remediation. If we know anything, we know that building envelopes will get wet – the question is, “where will the water go?” Make sure you know the answer throughout construction, especially as you seal joints…

2-1a-500x3892x
Diagram courtesy of Hammer and Hand’s Best Practices Manual.

… Joint Rule of Thumb: Sealant should be hourglass-shaped and width should be twice depth (shown in diagram).
Backer rod diameter should be 25% larger than the joint to be filled.
Joint size should be 4x the expected amount of movement (usually about 1/2” of space on all sides of the window casement).
Ideal joints are within a range of 1/4” at minimum and 1/2” at maximum. Joints outside this range require special design and installation.
Always use the right tool: sealant is not caulk and should never be tooled with a finger (saliva interferes with bond).
Substrates need to be clean, dry, and properly prepared (primer if necessary).
When dealing with thermally sensitive materials, apply sealant under average temperature conditions because joints expand and contract with changes in temperature…”

backer-rod-by-header
Example: Piece of backer rod being inserted into gap between header and 2×6.
garage-mudsill-w-gasket-and-sealant-corner
It’s not visible, but the wood-concrete connection at the side wall has a piece of backer rod embedded between the two materials, making it easier for the sealant to bridge the gap over the long term.

Air Sealing: Rim Joist – Floor Joist – Mudsill Connections

Since there was time between completion of the rim joist/floor joist installation and the installation of the sub flooring (a weekend), I took the opportunity to seal up all the visible connections.

installing-floor-joists-w-bill-johnny
Billy and Johnny installing the floor joists.

Once the subfloor goes in, these connections are still accessible from inside the basement, but the space to work in would be really cramped and uncomfortable (at least I thought so).

rim-joists-box-before-caulk
Rim joist – floor joist – mudsill connections prior to sealant being applied.

The same areas after applying the sealant:

I found the silver Newborn sausage gun (photo below) worked great for thick beads under the mudsills, but the blue gun worked even better for all other seams. Because the blue gun utilizes disposable tips, it was easy to cut the tip to exactly the size I needed, thus using (wasting?) less material (and hopefully saving a little bit of money).

An added benefit of the disposable tips is less time required for clean up at the end of the day (always a good thing). Both guns work great, and appear to be really well-made, although I would probably only buy the silver one again if I consistently needed a fat bead of sealant.

newborn-sausage-guns
Newborn sausage guns I found on Amazon. The blue one works great for thin beads, the silver for thicker beads (e.g., under mudsills).

In the photo below, I filled larger gaps with either backer rod, or in the case of the largest gap, bits of pulled apart Roxul Comfortboard 80, before applying the sealant. Since this is the first time I’ve done this, these are the kind of connections that I failed to anticipate beforehand. They are definitely worth planning for.

The temptation is to just fill these kinds of voids with sealant, but for the long-term durability of the connection backer rod or some kind of insulation stuffed into the gap is a better solution. Filling the voids before sealing doesn’t take much additional effort, so it’s definitely worth taking the time to do it right.

Knee Walls Installed

Because our lot is sloped, the plans called for a series of knee walls:

knee-wall-going-up
The guys installing the knee walls (left to right: Johnny, Nils, Sammy, and Billy).

When I saw the first piece of Zip about to be installed, I realized the bottom edge, which is exposed OSB, would be sitting directly on top of the Roxul on the foundation. While it’s unlikely that water will find its way to this edge (the flashing for the wall assembly will be installed over the exterior face of the Zip at the bottom of the wall), it seemed like a good idea to tape this edge with the Tescon Vana for added protection and peace of mind (even if it only protects this exposed edge until the rest of the wall assembly is installed).

zip-first-piece-attached
First piece of 7/16″ Zip wall sheathing installed.

Knee wall pictured below had all exposed seams in the framing lumber filled with the Contega HF sealant before also applying the Tescon Vana tape, all of which was done prior to the Zip sheathing being installed. The sealant takes about 48 hours to cure enough before you can effectively cover it with the Pro Clima tapes (something to consider when setting up scheduling goals).

20170105_121618
Knee wall being covered in Zip sheathing.
zip-on-framing-covering-tescon-vana-w-roxul-below
Close-up of knee wall with Zip sheathing and sealed seams.

For the bottom, exposed edge of the Zip sheathing, I cut the Tescon Vana tape like I was wrapping a present…

Once the Zip sheathing was installed on the knee walls, I could move into the basement and seal up the connections between the Zip and the framing members, in addition to hitting any seams in the framing itself.

Once the house gets closed in, I will go back and tape the connection between the top of the foundation and the mudsill for one last layer of protection against air infiltration.

sealing-up-the-inside-of-the-knee-wall-stud-bays
Knee wall with Zip sheathing after sealing up all the connections.

Subflooring

We decided to use Huber’s Advantech Subflooring after years of reading about it in Fine Homebuilding magazine, and based on the online comments from installers who see the added benefits that come with what is an admittedly higher price point. For instance, it’s more resistant to moisture, so it should produce more stable, flatter flooring (e.g. hardwood or tile) when the house is complete, in addition to preventing annoying floor squeaks.

Billy Phil Nils first pieces of subflooring
First sheets of subflooring being installed by Billy, Phil, and Nils.

In order to maintain a high level of indoor air quality (IAQ), we’ve been seeking out low or no VOC products. So, in addition to the Advantech subflooring, which is formaldehyde-free, we chose the Liquid Nails brand of subfloor adhesive (LN-902/LNP-902) because it is Greenguard certified. Another great resource for anyone trying to build or maintain a “clean” structure is available at the International Living Future Institute website: The Red List

liquid-nails
The product takes much longer to dry when it’s cold and wet outside — at least 2-3 days in our experience (sometimes even longer). It’s nice to see more “green” products showing up in the big box stores, rather than having to always special order them.
view-of-water-tower-from-kitchen-doorway
Standing by what will be the kitchen door. The subflooring was installed with nails and Liquid Nails subfloor adhesive.
rim-joists-at-outside-corner-sealed-up
Corner of our slowly growing wall assembly. The connection between the subflooring and the top of the rim joists was eventually sealed with the Contega HF sealant. 

Basement slowly being covered by subflooring:

Walls Go Up

Our wall assembly is almost entirely based on Hammer and Hand’s Madrona House project, which I discuss here: Wall Assembly

subfloor-done-blank-canvas
Our blank canvas.

In preparation for construction, I built a mock wall assembly in order to easily explain to anyone on site how the various components should go together. It also gave me a chance to practice using the Contega HF sealant, along with the various Pro Clima tapes from 475 High Performance Building Supply.

It’s been exciting to see the walls go up, incorporating the many details in the mock wall assembly.

men-at-work
Men at work: Zach, Phil, and Sammy laying out the walls.
zip-going-on-the-walls-w-bead-of-adhesive
Zach and Phil installing the Zip sheathing over the framing.
zip-sheathing-w-phil-putting-on-continuous-bead-of-adhesive
Phil laying down a consistent and continuous bead of construction adhesive (trying to avoid a bead that runs back and forth between fat and thin), before the Zip sheathing is installed.
wall-being-prepped-w-tescon-vana-on-seams
We were fighting the rain, ice, and mud, but I was able to get the Tescon Vana tape over some of the seams in the Zip sheathing before the walls went up.
sealant-on-nail-holes-in-zip
Sammy and Billy help me apply the Contega HF sealant to each nail hole, and then make it lie flat with a swipe of the spatula, so the Tescon Vana tape that will be applied later will also lie flat.
zip-sheathing-prepped-w-tescon-vana-and-sealant-on-nail-holes
Section of wall nailed, taped, and nail holes caulked — ready to be raised up.

The final step before the walls were raised was to staple the B75 gasket to the bottom of each sill plate.

billy-zach-sammy-south-wall
First section of wall going up: Billy, Zach, and Sammy doing the heavy lifting.
phil-zach-plumb-sammy
Zach establishes plumb, while Phil readies to make the wall secure.
all-together-south-wall
The guys continue with the south walls.

View from south-east corner of the house with the guys framing in the shadow of the water tower:

The only section of wall where the B75 gasket rolled up on itself is shown below — no doubt because this was the most difficult section to get into place because of the stair opening. Otherwise, the guys had no issues with the gasket.

Even on this wall where the gasket did roll up on itself, I will cut off the excess that ended up on the interior side before sealing the connection with the subflooring, and then spend some time filling the void on the exterior side with backer rod and sealant as well.

east-wall-at-stairs-in-place-gasket-roll-up
Zach is the only dedicated, full-time framing carpenter on the crew (the other guys do a variety of carpentry-related work). He has a production background, and it shows with the energy and ease with which he works. He clearly enjoys what he does for a living (In photo: Zach, Sammy, and Billy). Sammy and Billy may not realize it yet, but they’re learning a lot from him (even if he does razz them all day long).

Below you can see some of the junctions where different materials meet, and the effort that’s going into air sealing these inevitable gaps: sealant at rim joist corners, rim joist – subfloor connection, and gasket under the wall sill plate:

wall-at-corner-w-b75-gasket-underneath
Wall is up.
wall-at-corner-w-b75-gasket-view-down-ext-side-of-wall
Same corner as above, but now looking down the exterior side of the wall.

We’ve tried very hard to keep foam out of the wall assembly and the overall structure itself (based on environmental concerns), however, one place where it did find its way in was the insulated headers for above our windows and doors:

billy-and-sammy-insulated-headers
Billy and Sammy putting the insulated headers together.
4th-wall-missing-from-backyard
End of the day. The fourth wall awaits.
east-facade-w-zip-sheathing
First look at what will become our front facade.

Once the perimeter walls were up, I went around with an impact driver and decking screws to tighten the connection between the Zip and the framing members, especially at the top of the walls. Although the Liquid Nails adhesive helps a lot, it still makes for an imperfect connection between the sheathing and the framing members:

top-of-wall-assembly-looking-down-gap-w-nail
Looking down at the top plate. The visible gap is between the side of the top plate and the Zip sheathing. I was able to close gaps like this one at the top of the walls using decking screws. The decking screws also closed similar gaps around window and door rough openings. This should make sealing these areas easier, and the connection more durable.
leaning-over-top-of-zip-sheathing
Leaning over the top of the wall to install the decking screws.

Having seen construction adhesive and nails in action, I would recommend a glue-and-screw approach if you’re trying to fully maximize the tightness of the connection between the sheathing and the framing.

sealant-with-water-tower
Nice view as I apply the sealant.
blue-chicken-pox
My wife giving our Zip sheathing blue chicken pox with the Tescon Vana tape in order to seal all the nail holes.
tescon-vana-embedded-in-ice-on-sill
It’s difficult to see, but this tape is embedded inside a sheet of ice. It rained overnight, before turning to ice. We’re asking a lot of these tapes and sealants. This piece of tape looks like fingertips holding on for dear life.
beast-looking-at-view-from-br-for-1st-time-close-up
The Beast gets a first glimpse of the view from her bedroom window.
pro-clima-pressfix
I was wondering why I would ever need more than one of these. Now I know — bent, scratched, and cracked, the Pressfix from 475 HPBS did its job well.

Foundation Details (Air Sealing #1)

14

Footings

For the top of the footings we used a product from Cosella Dörken called Delta Footing Barrier. Acting as a capillary break, the membrane is supposed to help prevent moisture from wicking up from below the footing, where it could then migrate into the foundation wall and into the basement, or even the wall assembly above (worst case scenario), causing mold or other moisture related damage. It should contribute to making the basement a very livable space (especially when combined with significant amounts of insulation on the exterior walls and under the slab).

Here’s a detail from the construction drawings:

footing-thermal-bridge-up-from-soil
Red arrow shows thermal bridge and gap in the vapor barrier up through the footing from surrounding soil if Delta membrane were not present.

In other words, this junction represents a weak point in our thermal envelope and vapor barrier. Passive House proponents often talk about using a red pen on a construction drawing to follow the air barrier and thermal envelope (the goal: no gaps in air sealing or the layers of insulation) . In theory, you should be able to do this all the way around the structure without once lifting your pen. If you can lift your pen (meaning there’s a gap in your air barrier or thermal envelope — which would be the case without the Delta membrane on top of our footing), then it’s a weak point that should be addressed (if at all possible).

Even with significant insulation on the exterior wall of the foundation (Roxul Comfortboard 80: 2″ + 3″), along with a sprayed-on waterproofing membrane, as well as a vapor barrier (Stego Wrap) and insulation (Roxul Comfortboard 80: 2″ + 2″) under the basement slab, this junction where the three elements meet — slab, footing, wall — is a weak point. Although it doesn’t address the weakness in R-value, at least it should keep the moisture at bay (probably the biggest complaint associated with basements).

With a 9′ basement, we’re hoping the temperatures at this depth are consistently mild enough to avoid any kind of significant energy penalty. I’m confident this will be the case because in our last home, a typical suburban tract house without much insulation, the basement always stayed cool in the summer and warm in the winter, even though the ducts to the basement had been closed off so the space never saw any direct benefit from the HVAC system.

For minimal cost in materials, the Delta membrane seems well worth it for the added peace of mind.

foundation-delta-membrane-in-box
Rolls of Delta Footing Barrier on site and ready to go.

Here is a video and some photos from our job site:

The guys from Tynis Concrete didn’t seem to mind trying something new, and the membrane went on without any issues.

foundation-delta-fabric-close-up-in-corner
A corner of the footing with the Delta membrane “keyed” into the footing.

I couldn’t find any local suppliers who carried the Delta membrane, so I ordered online from: spycorbuilding.com

foundation-mud-shot
Detail of the bottom of our hole, being prepped for the footings.

Foundation Walls with Roxul Comfortboard 80

For the walls, first we used a spray-on waterproofing membrane from Tremco:

After the waterproofing was complete, we began installing the two layers of Roxul Comfortboard 80 (a dense, rigid form of insulation that can be used below grade, to the exterior side of wall sheathing, and even under a basement slab), which will give the basement foundation walls an R-20 of insulation value.

roxul-delivered-to-the-site
Roxul delivery shows up on site (Comfortboard 80: 2″ and 3″ thick). Roxul is showing up in the Big Box stores here in the Chicago area, so it’s becoming easier to order.

When questions came up about how to install Roxul, or which product to use where, their technical help via email was great — in our case, Fiona Schofield, who gave us a lot of useful information — including the document below, a study on the long-term condition of Roxul (aka stone, rock, or mineral wool) in a below grade application (i.e. up against an exterior foundation wall):

external-thermal-and-moisture-insulation-of-outer-basement-wall (pdf)

In addition, after finding the video below online, in which what looks to be a European version of Roxul is attached to a cinder block wall with an adhesive, or a thinset mortar,

I contacted Fiona and heard back that it was ok to use an adhesive for our first layer (PL Premium, or similar polyurethane adhesive caulk), so long as we used a mechanical fastener for the second layer. In effect, the first layer just needs to stay on long enough for us to get the second layer up and attached with a mechanical fastener. This really saved us some time since the guys didn’t have to drill two full sets of holes.

sammy-butters-the-back-of-the-roxul
Sammy hitting the back of the Roxul with Liquid Nails before setting it into position. The adhesive worked really well at keeping the Roxul in place, even when the foundation was damp in certain areas.

The guys also didn’t seem to mind cutting or otherwise working with the Roxul. We used serrated knives we purchased from Home Depot, made especially for cutting rock wool…

serrated-knife-for-roxul
This knife, purchased from Home Depot, works really well cutting the Roxul.

…which worked fine, but then after some experimenting, the guys also began using a small, handheld sawzall (reciprocating saw), and even a table saw, to get the exact-sized pieces we needed to ensure staggered seams. I had my doubts about the table saw, but Phil said the Roxul cut easily, and it really didn’t seem to kick up a lot of dust (although he did wear a dust mask for protection).

nils-and-bill-getting-1st-layer-of-roxul-up
Billy and Nils (in the hole in the background) gluing up the first layer of Roxul.

Once the first layer of Roxul (2″ thick) was in place, we could then install our second layer of Roxul (3″ thick) over the top of it.

After a lot of research, and even posting a question on Green Building Advisor…

Attaching Roxul Comfortboard 80 to Exterior of Foundation Walls

…we decided to go with the Rodenhouse fastener (Plasti-Grip PMF):

These really are as easy to install as depicted in the video. Using a hammer drill with a 5/16″ bit, the guys drilled a hole to the depth of the fastener, before tapping the PMF fastener home with a hammer. It’s a genuinely straightforward process. Sometimes a fastener wouldn’t sit perfectly, but as long as a majority of the fasteners on each board did, it didn’t seem to be a problem. Based on what I read online, they were much easier to work with than if we had to use Tapcon or similar concrete screws.

rodenhouse-fastener-close-up
Close-up of the Rodenhouse PMF fastener.

They weren’t cheap, but they were well worth the cost in materials for the savings in labor (and frustration). And Mitch Mahler, from Rodenhouse, was easy to work with via email in terms of ordering or getting answers to technical questions.

rodenhouse-fastener-box-w-label
The box the fasteners came in.
in-the-trenches-w-roxul
In the trenches, as the second layer of Roxul gets attached with the Rodenhouse fasteners.
long-narrow-piece-of-roxul-w-3-fasteners
Long, narrow piece of Roxul with 3 Rodenhouse fasteners.

Normally, Roxul recommends 5 fasteners per piece (4 in the corners, 1 in the middle), but we found that 4 on a normal piece, and 3 for a long, narrow piece worked fine — at least for the foundation, where the backfill will help to keep the Roxul in place over the long haul.

Thermal Bridging in the Foundation

Following Passive House science principles, we tried to remove as many points of thermal bridging in the structure as we could. One area where this was addressed in the construction drawings was a 7″ thermal break between the basement foundation and the attached garage foundation. In other words, there would be no physical connection between the garage and house foundations at all. The only connection would occur above, at the level of framing, where they would be tied structurally together. The idea was that we could place our two layers of Roxul (2″ + 3″) in that gap, thus maintaining our 5″ of Roxul on the exterior of the foundation, uninterrupted (the key point here) around the perimeter of the basement foundation.

On the day the footings were installed, however, our concrete subcontractor expressed serious reservations about the long-term structural stability of the framed house and garage above this gap — in effect, he was worried that over time the two foundations might settle and move apart, wreaking havoc with the framed structures above.

So I was back to post another question on Green Building Advisor (a fantastic resource for any green build or self-build) on the topic:

How important is a thermal break between a house foundation and an attached garage foundation?

Here are some photos showing these connections:

foundation-north-corner-garagehouse-connection
Garage foundation meeting up with corner of house foundation (north side of house).
foundation-garage-house-connection-north-corner
Close-up of this garage-house foundation connection, from inside the garage.
foundation-front-porch-garage-to-house-porch-to-house-connections
Front porch. Thermal bridge from garage to house is off to the far right.
foundation-garage-house-connection-inside-corner-of-garage-inside-corner-of-front-porch
Inside corner of garage where garage-front porch-house connect.
foundation-front-porch-to-house-connection-outside-corner-of-porch
Outside corner of front porch. Technically, another thermal bridge from porch to house foundation.
foundation-side-porch
Wing wall for side porch stoop. Yet another thermal bridge to the house foundation.

Unfortunately, there just doesn’t seem to be a lot of information available as to how to proceed. In the end, we decided to ignore these connections, hoping that the thermal bridging at these two points (garage-house, garage-front porch-house), in particular, won’t be all that significant (to our heating and AC costs, or, for example, cold getting into the foundation and then rising up and getting into the wall assembly above these two points where it could become interstitial condensation — unwanted, and potentially dangerous, moisture in the wall).

I assumed Passive House builders would incorporate rigid foam insulation into the concrete forms at these points, but I couldn’t find any pictures or descriptions showing or talking about this in books, magazines, or anywhere online. Either Passive House builders ignore these kind of connections, or I just missed the information somehow. 

*** If anyone knows of good sources on this, let me know, and I will post links here to help others in the design stage of their own build ***

Update: David Goodyear is building a Passive House in Newfoundland, and he has successfully used rigid foam between the house and garage foundations. You can read about it on his blog here:

Flat Rock Passive House: A Tale of Two Foundations
foundation-side-porch
BEFORE: Monument to Italian Brutalism.
side-porch-getting-wrapped-in-roxul
AFTER: Wrapped in snuggly blanket of Roxul. The wing wall was eventually entirely covered except for the tops.

Below are the other points of thermal bridging in the foundations, now covered in Roxul:

south-inside-corner-of-garage-w-roxul
Corner of garage foundation meeting up with house foundation (standing inside garage).
south-view-of-garage-house-foundation-connection-w-roxul
Same corner, from outside, looking at house foundation to the right.
inside-garage-garagehouse-connection-w-roxul
Garage-front porch-house connection (from inside garage).
front-porch-w-roxul
Outside corner of front porch meeting up with house foundation.

We did our best to cover these thermal bridges, but clearly it’s imperfect, so all we can do is hope there won’t be a significant energy penalty associated with these connections.

Basement Windows and Roxul

As the Roxul was going on the foundation, Phil and Nils installed window bucks for the two basement windows. The bucks were sized so they meet up flush with the two layers of Roxul. Eventually a layer of HardieBacker board and two coats of Tuff II (the product we’ll be using for the parge coat) will cover the window bucks, and also the transition between the top of the foundation walls and grade around the perimeter of the house.

nils-installing-basement-window-bucks
Nils installing the basement window bucks as the Roxul is being installed on the exterior side of the foundation.

I initially intended to use the R-Guard line of liquid membranes by Prosoco for air sealing and waterproofing all seams and window/door openings, but cold temperatures made this impossible (they require 40° F and rising, which would be the exception rather than the rule here in Chicago for December and January). Maybe because of years house painting (caulking and drywall patching) the liquid membranes seem easier to use and less fussy to get right (the big issue with the tapes is avoiding wrinkles and properly shingle flashing to get water moving in the right direction).

Our Plan B was the series of Pro Clima products sold by 475 High Performance Building Supply. Most of them, including the sealant, can be used down to 14° F without issues.

Another option would’ve been the line of Siga tapes, another popular choice used in Europe, available from Small Planet Supply.

So as the window bucks went in, I followed, applying Contega HF sealant to all the seams and gaps. The sealant is acting as our first layer of air blockage. It’s super sticky, so I don’t doubt that it’s permanently flexible. I did a mock-up of our wall assembly months ago, and the HF on the seams is still tacky to the touch. It goes on light green, then slightly darkens as it dries.

contega-hf-sealant-in-20-oz-sausage
Contega HF sealant in a 20 oz. sausage. It’s also available in the more familiar 10 oz. caulk tubes.

A few suggestions for using the HF Sealant:

  • I’ve found that completely snipping off the metal clip on the end of the sausage (as opposed to just cutting a couple of small slits around it) prevents it from getting jammed in the front end of the gun.
  • If I have a half-finished sausage of HF at the end of the day, I put it in a tightly wrapped plastic bag overnight (see photo below), which allows me to use it within a day or two without any problems.
  • Use a tiny spatula (see photo below) to tool the HF into place rather than your finger, as you normally would with a caulk — it’s just too sticky.
  • Because the HF is so sticky, I wear Nitrile gloves, so when it starts to get everywhere — and it will get everywhere if you let it — I just simply change to a new pair.
  • For clean up, the Citrus Solvent we’ve been using with the tung oil works great.
newborn-sausage-gun
The Newborn brand of sausage gun we’re using for the HF sealant. Found it on Amazon. A really well-made tool.
ateco-spatula
Found this on Amazon. I thought it was construction grade, but it’s made for kitchen use. It’s durable, and I like the thin blade since it offers more “feel” than a thicker blade, making it easier to tool the HF into place without displacing too much of it in the process.

It’s easy to forget the realities of a construction site when planning details, like the use of the Pro Clima tapes. I pictured it being a pretty straightforward process, not a winter day in the 20’s, fingers numb, propped up on an unbalanced ladder in the hole, while the other guys are cutting wood and Roxul around me — a case of adapt or die, I guess, and a reminder not to be overconfident about the products you’ll be using, or the installation process that inevitably goes with them.

installing-pro-clima-tapes-on-ext-side-of-base-wdw-bucks
Applying the Pro Clima tapes to the exterior side of the window bucks.

It was important that the connection between the window bucks and the concrete of the foundation be air sealed and made water tight before it gets completely covered by the two layers of Roxul.

It’s been in the 20’s and 30’s, so the HF sealant took a couple of days to firm up before I could then apply the series of Pro Clima tapes. I’m using a combination of tapes, including the Tescon Vana (the bright blue), Profil (light blue — great for making inside and outside corners), Contega Solido Exo (black, 6″ wide), and the Extoseal Encors for our sills (475 HPBS has a great series of videos showing how to use each tape).

installing-pro-clima-tapes-on-basement-window
Finishing off the buck from inside the basement.

We knew the bucks would be sitting for some time, exposed to the elements, before the windows actually show up, so we decided to completely cover the openings just to be safe. This gave me extra practice using the tapes, which definitely helped, and it meant not stressing out every time the forecast called for rain or snow.

basement-window-buck-covered-in-tape
Basement window buck covered in Contega HF sealant and Pro Clima tapes.

The only tape that’s giving me fits is the black Contega Solido Exo. It’s thinner than the other tapes, so it has a propensity to want to stick to itself (wrinkles are more difficult to avoid), and I find it much harder to pull it away from its peel-and-stick backing than the other tapes. I worried that the Extoseal Encors might be difficult to get right, but it — along with the Tescon Vana and Profil tapes — has been surprisingly easy to work with.

This video was my Bible for installing the Extoseal Encors:

In lieu of on-site training from someone who’s used a specific product consistently, videos like this one are invaluable when using new products and you want to get the details right. Without videos like this, you’d be in for a frustrating process of trial and error.

For instance, even with this excellent video, I noticed when I did our mock wall assembly that because the Extoseal Encors can stretch around corners it’s easy to stretch it too much, thereby inadvertently thinning it out. I’ve found that when I get to a corner it’s better to just fold it around the edge rather quickly, without overthinking it too much, which helps to maintain the thickness of the material at and around the corners (arguably the product’s strongest attribute in helping to avoid water damage).

I can’t recommend enough doing a mock wall assembly, or practicing on scraps, to get a feel for using these products, before you find yourself on-site doing it for real.

basement-window-buck-before-roxul
Basement window buck sealed and taped on the exterior side before being covered in Roxul.
close-up-basement-wdw-buck-covered-by-roxul
Basement window buck surrounded by two layers of Roxul.
basement-window-buck-and-roxul-meet-up
Close-up of outside edge of basement window buck and Roxul connection.

We’re almost ready to climb out of the hole. It will be exciting to watch the guys start framing so we can see the basic form of the house begin to take shape.

foundation-tools-ready-to-leave-site
Tools ready to head to the next job site. Concrete guys (they’re mostly guys) are the unsung heroes of construction (excavators should be included as well) — like offensive linemen in football, no one pays much attention to them until a mistake is made.
foundation-concrete-jewelry
Concrete jewelry.
queen-of-dirt-mountain
Queen of Dirt Mountain.

“How did I get here?…”

0

So Why Build an Eco-friendly “Green” Home Anyway?

In the summer my wife and I teach a class together, called Excel 2, which is one small component of a larger, overall Excel Program (my wife is a high school Social Studies teacher).

Typically, Excel students come from first-generation immigrant families. They are college-bound students who have exhibited great potential, but who are in need of some encouragement, particularly in regards to taking Advanced Placement (AP) courses (huffington post). For most of our students, they will be the first ones in their family to attend college, so it is understandably an intimidating prospect in any number of ways.

The course itself is three weeks in the summer session, its focus on developing reading and writing skills by utilizing non-fiction reading assignments. We emphasize the importance of correct spelling, proper grammar usage, and attention to detail by requiring multiple revisions to several thesis paragraphs, which are themselves based mostly on college-level reading assignments.

You can imagine how well this goes over with incoming high school sophomores and juniors — especially in summer. We’ve tried to overcome this dilemma (how to motivate young high school students to tackle a course based on rigor when many of their friends are out enjoying summer break) by delving into topics they are intimately familiar with, but hopefully in ways they have not yet confronted.

IMG_9702
Some of our Excel students with my wife, Anita: (front row) Aubrey and Imani, (back row) Eduardo, Anita, Cecelia, and Karen. 

As a whole, 50% of the students attending Palatine High School qualify for free and reduced lunch. Not surprisingly, then, the Excel students face some unique, if not daunting challenges, both in and out of the classroom. In addition to the normal stresses associated with being a teenager, many of them deal with balancing school work with long work hours at low-paying jobs (helping their families make ends meet), social pressures to stray down the wrong path (in any number of ways), and even (most heart-breaking of all) confronting what researchers term being food insecure — in plain English, not always knowing when or where they will get their next meal.

We present the class to the students as an opportunity to test themselves, to really see where they are, currently, in terms of a whole host of skills. The main goal of the Excel 2 program, therefore, is to really challenge their abilities, not just in terms of reading and writing skills, but also soft skills such as interpersonal communication, the importance of body language, time management, and self-discipline.

Essentially, we try to give them a college-level course experience, hoping it better prepares them for the eventual reality. In other words, we’d rather they struggle in high school with us than have it happen when away from home for the first time, off on their own, at college  (atlantic)  (newsweek)  (washington post).

Here’s an example of our ever-changing syllabus:  Excel 2 – 2015

As you can see from the reading assignments, we encourage our students to start asking questions about everyday things they may be taking for granted. We hope this sharpens critical thinking skills, but we also hope it encourages them to be more active participants in their lives, rather than just sleepwalking through their days as passive consumers.

Consequently, when it came time for us to find a new place to live, we saw it as a good opportunity to practice what we preach:

  • What exactly do you want from a new house?
  • If you’re going to buy a house (and you’re lucky enough to even contemplate doing so), what should it look like? A condo? A townhouse? Or a single-family residence?
  • In which neighborhood are you going to buy?
  • How many square feet do you want (or need)? How many bedrooms? Do you want (or need) a formal living room or dining room? Do you want (or need) a basement?
  • What architectural style appeals to you?
  • How are you going to furnish the interior?
  • Should you care about indoor air quality (IAQ)? And if you do, how do you protect it or improve it?
  • What do you want in your walls and attic for insulation? How much do you need?
  • How much will utilities cost? Are there cost-effective ways to reduce those costs?
  • Are renewables — solar, wind, or geothermal — worth considering? How long is the payback period?
  • Do you want your house to be environmentally friendly — and what does that mean anyway?

Instead of moving into the typical, leaky, not very environmentally friendly suburban condo, townhome, or house (we were leaving behind the latter), we thought it would be more interesting to see just how “green” we could make our next house.

Because we wanted a yard to do plenty of landscaping and gardening, we narrowed the choices down to a single-family house. And, instead of tackling the challenges that come with a retrofit, we decided to try building new.

Much like hearing Jonathan Ive talk about an Apple keyboard, we appreciated the detail required to meet the certified Passive House standard. At the time (summer 2014), this seemed like the way to go.

After the experience we had with our original builder (2015), and then subsequently trying to learn as much as possible about the Passive House standard, in addition to discovering the Pretty Good House concept along the way, our house plans have evolved into a kind of 3-headed hybrid: Passive House science + Pretty Good House + Net Zero (Zero Net Energy: ZNE).

The goal of all three: dramatically reduce the energy consumption of our house as much as possible (especially our dependence on the energy grid). We also want to do a significant amount of planting and growing in our yard, mostly xeric plants that require little additional watering, in order to combine house and yard into an eco-friendly system of sorts.

Our last home (approx. 2800 sq. ft.) was a fairly typical suburban tract house. It had builder-grade windows and doors (most of which had to be replaced after just a few years), very little insulation in the walls (the switch for the back porch light would actually ice up when temperatures fell below 20° F), and it had a great deal of under-utilized space (e.g. a two-story foyer, a formal living room and dining room, and a fourth bedroom, all of which saw little use).

With our new home (just over 1500 sq. ft. of living space), we’re trying to turn all of this on its head so we end up with something we really want and will enjoy. To paraphrase Kevin McCloud: ‘maybe it’s better to have a little bit of something special than a lot of something mediocre’.

An oft-quoted statistic (1)­ suggests a significant amount of our greenhouse gas emissions can be attributed to our structures (typically the figure is in the 40-50% range) — including residential, commercial, industrial, and governmental — so maybe change really does begin at home (SA) (greenbelt movement).

(1) According to a recent Fine Homebuilding article, “Better Than Average”, by Brian Pontolilo: “It’s not clear how much our homes contribute to greenhouse-gas emissions and to climate change. The most recent data available from the Department of Energy is from 2009-2010. Outdated as it is, this data indicates that residential buildings contribute around 20% of total U.S. greenhouse-gas emissions. This includes fossil fuels used on-site (e.g. natural gas for cooking and heating) as well as electricity.” (September, 2016 issue, p. 64)

The title of this blog entry was lifted from a lyric in this Talking Heads song: