kimchi & kraut

Passive House + Zero Net Energy + Permaculture Yard

Tag Archives: Tescon Vana

Siding Part 1: Continuous Insulation with a Rainscreen

10

Continuous Insulation vs. Double-Stud Wall

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

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

 

High R-Walls

 

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

 

Passive House Lessons

 

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

 

 

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

 

 

2 Layers of Rockwool over Zip Sheathing

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

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

Wall Assembly

 

 

Finding Subcontractors for a Passive House

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

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

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

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

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

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

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

 

 

Installing Rockwool over the Zip sheathing

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

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

 

 

 

 

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

 

 

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

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

 

installing head flashing above wdw

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

 

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

 

z flashing nw corner

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

 

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

 

1st pcs rockwool going up n side

Putting up the first pieces of Rockwool on the north side.

 

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

 

orange cap nails for 1st layer rockwool

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

 

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

 

1st layer rockwool n side

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

 

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

 

20171002_081038

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

 

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

 

1st layer rockwool at wdw buck

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

 

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

 

starting 2nd layer rockwool n side

Mark and Wojtek beginning the second layer of Rockwool on the north side.

 

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

 

2nd layer rockwool at utilities

Second layer of Rockwool installed around mechanicals. Note the sill cock, or hose bibb: although it runs into the house, we left it loose so that it could be adjusted until the siding was complete — only then was it permanently soldered into place.

 

 

weaving outside corner w: 2nd layer

Weaving the seams at the outside corners to avoid undermining the thermal performance of the Rockwool.

 

 

2nd layer rockwool fastener at wdw

Close-up of the fasteners we used to attach the second layer of Rockwool.

 

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

 

plates for 2nd layer rockwool

 

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

 

trufast screw bucket

 

 

inside bucket trufast screws

The Trufast screws and plates were purchased from a local roofing supply house.

 

 

w side 2 layers rockwool

West side of the house with 2 layers of Rockwool complete.

 

 

1st layer rockwool into s side garage

First layer of Rockwool filling the gap between the house and garage framing.

 

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

 

2nd layer rockwool closing gap at garage

Second layer of Rockwool closing the gap between house and garage completely, ensuring our thermal layer is unbroken around the perimeter of the house.

 

 

nw corner 2 layers rockwool

Northwest corner of the house with the 2 layers of Rockwool installed.

 

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

 

 

Installing Battens and Creating our Rainscreen

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

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

 

 

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

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

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

 

 

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

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

 

headlok missed framing

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

 

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

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

 

monkey on furring strips

The Beast testing out the structural integrity of our strapping on the garage. Note the Cor-A-Vent strip below the bottom horizontal furring stip, helping to establish a ventilated rainscreen.

 

 

garage only 2x4s

Common wall inside the garage. Only a single layer of strapping was necessary in preparation for drywall.

 

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

 

recess 4 screws

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

 

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

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

 

rainscreen2.jpg

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

 

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

 

starting 1x4s n side

1×4’s being installed horizontally on the north side in preparation for the charred cedar that will be installed vertically. Also note the Cor-A-Vent strips just above the foundation and below the window.

 

 

cor-a-vent-product-label

The main product we used to establish our ventilated rainscreen.

 

 

insect screen for rscreen

Window screen we cut to size for added insurance at the bottom of the walls around the Cor-A-Vent strips.

 

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

 

shims behind 1x4s

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

 

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

Really impressive work by Wojtek and Mark.

 

lking down furring behind rscreen at fdn

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

 

 

rscreen furring at foundation

Strapping and rainscreen elements around a penetration near the top of the foundation.

 

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

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

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

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

 

Window Trim

 

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

 

Sills and Thresholds – Installation Details

 

wdw rscreen and frame detail

The many details coming together around a window. In addition, each window eventually received a dedicated metal sill pan as a durable way to ward off water intrusion.

 

 

from int wdw rscreen and sill

Looking through an open window to the sill and the rainscreen gap at the outside edge. Note the Extoseal Encors protecting the sill of our window buck.

 

 

lking down wdw rainscreen

Outside edge of the window sill, looking down into the mesh of the Cor-A-Vent strip with daylight still visible from below.

 

 

rscreen at hd flash on wdw

Head flashing at the top of a window with doubled up Cor-A-Vent strips above it.

 

 

out corner hd flshng ready for sd

Same area, but with a 1×4 nailed across the Cor-A-Vent, creating a nailing surface for the cedar siding.

 

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

 

kitch dr prepped 4 sd

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

 

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

 

frt porch prep - rscreen water

Front porch: elements in place to try and prevent moisture damage.

 

 

west w: 2 layers battens

West facade prepped for siding.

 

 

flashing details on porch

Wojtek and Mark did a nice job with all the metal flashing details around the house — these kind of areas are the unsung heroes of a structure that manages water safely, and unfortunately go largely unnoticed by most homeowners.

 

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

 

Mark and Wojteck at front door

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

 

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

 

Mark and Wojtek on the roof

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

 

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

HVAC Part 1: Zehnder ERV

6

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

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

 

 

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

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

UltimateAire

and

Renewaire

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

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

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

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

 

 

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

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

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

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

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

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

 

zehnder pile of parts

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

 

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

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

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

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

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

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

 

 

 

 

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

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

 

main unit attached to basement wall

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

 

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

 

marking comfopipe w: sharpie

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

 

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

 

drilling hole for Zehnder exhaust

Making initial cut in the Zip sheathing.

 

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

 

hole in Zip for heat pump pvc

Hole cut and ready for the ComfoPipe.

 

 

hole set-up for comfopipe

Hole made in our Zip sheathing, ready for the ComfoPipe from outside to make a connection with the section inside.

 

 

ext - comfo pipe going thru zip into basement

Ready to push the ComfoPipe into the house from outside to make the connection inside.

 

 

Zehnder chipmunk's back

Chipmunks are back.

 

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

 

comfo pipe thru zip

Making the connection between inside and outside.

 

 

setting up comfo pipe

Adding a Roflex gasket to make air sealing much easier.

 

 

comfo pipe sealed int.

ComfoPipe air sealed on the interior side with Roflex gasket and Tescon Vana.

 

 

close up comfopipe sealed

Close-up of the ComfoPipe air sealed at the Zip sheathing.

 

 

installing comfo pipe next to main unit

Finishing up the last sections of ComfoPipe as they leave the main unit.

 

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

 

comfopipe ext sealed and covered

Repeating the same air sealing process on the exterior for the ComfoPipe, adding black garbage bags over the opening with rubber bands to keep out dust, dirt, birds, and any critters that might otherwise try to enter the structure during construction.

 

On the outside, we made sure to extend the ComfoPipe out farther than we needed, giving us some leeway once insulation and siding were installed over the Zip sheathing. This allowed us to cut the ComfoPipe back to the proper depth before installing the permanent covers supplied by Zehnder.

 

comfo pipe ext close up sealed

Close-up of ComfoPipe as it exits the structure (before insulation, furring strips, siding, and its final cover).

 

As far as the white tubing is concerned, we really enjoyed how easy it was to put the 3″ ComfoTubes together.

During the design phase, and even after we brought the Zehnder unit to the job site, we always intended to place the diffusers for supply and exhaust points on ceilings. But after really looking at all the cuts in our ceiling service chase that would be required to make this happen, we decided to opt for placing all of them on walls instead.

It proved to be one of the better decisions we made during construction. Not only did we avoid having to make many cuts in our ceiling structure, which would’ve meant a struggle to appropriately map them out around conduit, ceiling lights, and plumbing vents, it had the added benefit of making it much easier to do ongoing maintenance at the diffusers, mainly checking on and cleaning filters, once we moved in.

 

cone diffuser filter

Cone shaped filter for exhaust diffusers (bathrooms, kitchen, laundry room, and basement in our case).

 

In fact, during commissioning, our Zehnder rep told me they have issues with homeowners not keeping their exhaust diffuser filters properly cleaned, effectively undermining the efficiency and overall performance of the units. This is understandable if the diffusers are on ceilings, whether at 8′ or 9′. It would be easy to forget about them, or even if you did remember, one can understand the reluctance to drag out a 6′ step ladder every time they needed to be cleaned. We were also told that placement of the diffusers is extremely flexible — almost anywhere can work (check with Zehnder directly just to make sure your proposed placement will work).

 

inside diffuser filter

Diffuser filter in bathroom after about a month. Once all the construction dust settled down from completing interior finishes, these filters don’t get dirty nearly as quickly as they once did — in other words, this isn’t bad at all.

 

By keeping them around 7′ off the finished floor, it’s easy for me to check and clean the exhaust diffuser filters on a regular basis (1-2) times a month. I always have 2 sets of filters, so it’s easy to remove the dirty ones, put in clean ones, and then rinse and dry out the dirty ones.

 

 

Once we decided to go through walls (both 2×6 and 2×4 framed walls), it was just a matter of deciding where in each wall we wanted the diffusers to be placed, and then cutting the corresponding hole through the wall’s bottom plate and the subfloor — being careful to check, and re-check, in the basement for any floor joists, plumbing, or electric conduit that might be in the way.

For bathrooms we placed the diffusers between showers and toilets, slightly cheating towards the showers to ensure maximum moisture removal.

 

changa drilling for tubes

Apparently cutting the holes through the floor looked like fun, since my wife was happy to take over this chore for me. The DeWalt we were using worked great until it crapped out on us a couple of holes short of finishing. We definitely noticed a difference going back to a normal drill and hole saw set-up.

 

At the unit itself, Zehnder supplied us with blue (fresh air) and red (stale air) tags, to mark each ComfoTube as it leaves or returns to the main unit. This should make any potential maintenance or repair issues in the future easier to resolve, as well as helping to avoid confusion as you set in place each pipe at a diffuser.

 

first few return tubes are in

Attaching the white ComfoTubes to the main unit, carefully labeling each pipe for future reference.

 

 

main unit w: exhaust tubing installed

ComfoTubes being installed at the main unit.

 

 

top of silencers #2

Close-up of the top of the main unit, as ComfoTubes are being installed.

 

 

Sydney helping us

Sydney, one of our former Excel students, was nice enough to stop by and help us pull the ComfoTubes from the basement up to the first floor.

 

 

OB helping us pull and set-up the tubes

OB was also nice enough to come back to help us push and pull the ComfoTubes into place for the diffusers.

 

 

spaghetti

Pulling more tubing than we need up to the first floor. Later it’s cut back to properly fit to the various diffuser boxes.

 

 

setting up a port

Putting together a diffuser box.

 

Since we’re leaving the basement ceiling unfinished, it’s an ideal place to see how all the components come together: ComfoTubes meet at the diffuser box, along with the final cover for the diffuser, in this case for supply air. As you can see in the photo, there’s plenty of room in the metal tube of the diffuser box for deciding exactly where to cut it off in order to establish the finished height for the diffuser cover. In the basement we left them at their full height since there didn’t seem to be much incentive to cut them back.

 

basement supply diffuser

Basement diffuser box with attached ComfoTubes and final diffuser head (supply in this case).

 

 

laundry rm zehnder

Exhaust point in utility room with only one ComfoTube.

 

All of the diffuser boxes required at least 2 ComfoTubes, except for the laundry/utility room, which only required one. Using one of the supplied black plastic caps made it easy to block off one of the outlets in the diffuser box. These black caps are also handy when pulling the ComfoTubes around into position since they help to keep out any construction debris.

 

laundry rm exhaust

One outlet in the diffuser box is blocked off for the laundry room since we only required 12cfm for this area (12cfm per opening/ComfoTube).

 

Our kitchen required the most cfm’s, at 36, so it required a special diffuser box and 3 ComfoTubes.

 

kitchen octopus

3-hole diffuser box (36 cfm) for kitchen exhaust.

 

Again, since we didn’t place it in the ceiling, we put it across the kitchen, basically on a diagonal from the stove. So far we haven’t had any issues with cooking grease or odors, and our range hood (recirculating) seems to be doing its job just as well.

 

sunlight coming down comfo tubes

Sunlight coming down the ComfoTubes into the basement from the main floor.

 

Using scrap lumber, we were able to give each diffuser its proper stability in the wall cavities. Although the mounting hardware for each diffuser box seems rather fragile, we managed to avoid any issues.

Applying a bit of hand soap around each opening in a diffuser box made getting a solid fit between the ComfoTube, the black O-ring, and the diffuser box fairly straightforward.

 

connecting tube in kitchen

Attaching ComfoTubes with black O-rings and sliding clips on the diffuser box.

 

 

tubes for octopus in kitchen

ComfoTubes for kitchen exhaust going through the subflooring and into the basement.

 

 

black 0 ring

Putting the black O-ring on the ComfoTube.

 

It was also fairly easy to get each ComfoTube exactly where we wanted it. Since they’re so small (at least compared to traditional sheet metal ductwork), the tubes are easy to manipulate and move around, whether over a basement beam, around plumbing, electric, or any other structural component that’s not easily relocated. As long as you don’t need to make a short 90° turn, the tubes are easy to work with, so I imagine they would be ideal for renovation work in older homes.

 

long shot before tightening comfo tubes

It was fairly easy to put the ComfoTubes exactly where we needed them to go.

 

With most of the ComfoTubes in place, we just needed to add a couple of walls in the basement before finishing up the last few ComfoTubes.

 

raising basement wall w: Jesus and Eduardo

Jesus and Eduardo were nice enough to come back to help me put up a couple of basement walls.

 

Once all the ComfoTubes were installed at all the diffusers and at the main unit in the basement, we were able to pull all the lines tighter for a less messy final installation.

 

spaghetti comfotubes

Before pulling the tubing tight.

 

Using 2×4’s, we created a little window for the ComfoTubes to pass through under the floor joists. This structure helped to get the ComfoTubes moving away from the main unit in an orderly way that made it much easier to organize all the tubing once it was all installed.

 

zehnder installed w: tubes

All the ComfoTubes pulled tight, up by the floor joists, kept in place with some plumbing hangers.

 

Using plumbing hangers also kept the ComfoTubes under control and organized.

 

hanger straps for comfo tubes

Straps used to corral the sometimes unwieldy ComfoTubes, which can resemble spaghetti if left unorganized. They also worked well at stabilizing the gray ComfoPipe.

 

The commissioning of the unit, after drywall was complete, was fairly easy and straightforward, apart from a couple of wiring and electrical issues that had to be dealt with by phone with a Zehnder rep beforehand. And ordering filters from the Zehnder website has also been a straightforward and painless process so far (they’re not cheap, but they do seem to be highly effective).

The only issue we’ve really noticed with the unit is during summer when outdoor humidity levels are high. Since the ERV is constantly running, there’s no way to avoid bringing in some humid air in the summer.

And, unfortunately, it’s enough so that our Mitsubishi heat pump set-up (a future Part 2 of 2 for HVAC details) can’t properly get rid of the excess humidity either, even as it keeps the interior more than adequately cooled. We tried setting the heads to dehumidify, but they just dropped the temperature (almost to 60° F) without budging the humidity in the house very much — the rooms were freezing and clammy. As noted earlier, an ERV just can’t handle elevated levels of humidity in the summer on its own.

By having meters in various areas of the house it’s easy to see when humidity levels become a problem (we’ve been happy with our AcuRite gauges). Last summer our solution was to buy a couple of small dehumidifies, one for the first floor and one for the basement. They worked, but they also ate up a lot of energy. Setting the Zehnder fan speed to LOW seemed to help somewhat, but not enough to avoid using the dehumidifiers. This summer we’re going to try a stand-alone Ultra-Aire whole-house dehumidifier, which should use less electricity, and it should perform at least as well, if not better, at removing excess humidity.

 

 

 

 

Having read that anything above 60% indoor humidity can be problematic, especially in tighter, high-performance homes, it was disheartening to see the numbers move towards 70% in early summer. This is what prompted the purchase of the dehumidifiers.

From everything I had read during the design phase regarding Passive House, I knew indoor humidity in the summer could be a slight issue, but having experienced it firsthand, it now seems obvious that incorporating a dedicated dehumidifier in any structure that will see elevated levels of summer humidity, even if it’s only expected to last for just a few weeks, is simply a necessity. Based on what I’ve read recently, it sounds like Passive House designers, who were already doing this for Southern US states, are moving towards doing it in states much farther north. Presumably this would also hold true for anyone designing a Pretty Good House as well.

Granted, 60-70% indoor humidity (or even higher) for a couple of weeks probably won’t ruin any structure, but for us, at least, keeping it in the 50-60% range during the hottest days of summer not only gives us some added peace of mind, regardless of the hit we’ll take in terms of overall energy use, but it’s also an issue of comfort (I grew up in a house without air conditioning and still have vivid memories —all of them bad — of enduring hot and humid summer days and, even worse, long summer nights).

Much like the initial complaints of overheating, due to excessive or improper placement of glazing, especially on southern facades, this issue with excessive humidity seems to be part of the evolution in understanding how Passive Houses, or high-performance homes generally, actually work in real-world conditions. Although the concept has been around since the 1990’s, anyone building to or even just towards the Passive House standard should know they are guinea pigs to some extent, no matter how well established the idea may be in building science terms.

In the winter, we’ve had no issues. When temperatures fall below 20° F, we set the Zehnder to LOW, in the hopes that it will reduce demand on the heat pumps slightly, and it seems to hold onto humidity somewhat when the cold air being introduced would otherwise be excessively dry. Indoor humidity levels have been pretty consistent: above freezing they typically stay around 40%, and when temperatures plummet towards zero or below they’ve still stayed in the 30-35% range. We’ve rarely seen indoor humidity drop below 30%, even on the coldest days, which definitely makes a difference on overall comfort levels. I’ve also noticed that wood flooring and wood trim doesn’t shrink nearly as much as it did in our last, conventionally built home.

Also, even when we experienced record low temperatures last month (January, 2019), hitting -24° F without windchill, the Zehnder kept on running without any issues. As far as we know, it never shut off to try and protect itself from the cold (our mini-split system did, but more on that later). The product literature is somewhat vague, only noting that low temperatures could cause a unit to shut off, but it’s unclear at exactly what temperatures or what combination of other environmental conditions might cause this to happen.

Most people either tape or use sealant on the gray ComfoPipe seams to block air leakage. During our blower door test no air leakage showed up, even with a smoke pen test. Nevertheless, during our recent cold snap some frost was evident on the ComfoPipe seams, so I’ll eventually caulk these seams with Pro Clima’s HF Sealant, since there must be some air leakage, be it ever so minor.

In terms of the boost function, when turned on it pulls from all the exhaust diffusers, not just a particular bathroom or the kitchen. Again, for the kitchen, even if we’ve been roasting garlic or cooking something else that’s equally pungent, by the next morning any cooking smell is usually completely gone. There’s never been any lingering smells emanating from the kitchen.

For the kitchen, when you want to utilize the boost function you just set the ComfoSense wall unit to HIGH (the Zehnder equivalent to a standard wall thermostat). Unlike the bathroom boost switches, which run on a timer (set at the main unit in the basement), when you’re done cooking you have to remember to go back and lower the fan speed, otherwise it just stays on HIGH.

The ComfoSense unit also can display error functions or tell you when filters at the unit need to be cleaned. It also has an AWAY function, meaning you can have minimal fan speed to exchange air while you’re on vacation instead of just unplugging the unit altogether.

 

 

 

boost rocker switch

Boost rocker switch in the bathroom.

 

The boost switch in a bathroom is set to run for 30 minutes on the highest fan speed. So far, this seems to be plenty of time for it to work properly. Unlike a normal bath fan, which tends to be quite loud, even when the Zehnder is in boost mode it’s still incredibly quiet, so guests need to know they only need to press the switch once — it is indeed working.

For the bathrooms, the boost function has been working really well at removing moisture after showers. Nevertheless, in the winter, when temperatures are below 20° F and we decline to use the boost function after showers (again, hoping to hold onto some of the added humidity), the bathroom humidity levels still quickly drop from the 60’s and 70’s back to the mid-30’s in less than an hour (and this is even when the Zehnder fan speed is set to LOW).

We’ve also been happy with the diffusers, in terms of installing/removing them when necessary, but also in terms of their overall look. Whether on more neutral colored walls, or something bolder, they just look nice in our opinion.

 

supply diffuser

Zehnder supply diffuser on a neutral background on the wall.

 

They’re subtle enough to blend in to the background, but attractive enough so when they are noticed they don’t stand out in a negative way.

 

Zehnder exhaust diffuser

Utility room with a Zehnder exhaust diffuser on a neutral background — around the corner from the clothes dryer.

 

 

diffuser w: bold colors in bg

Zehnder supply diffuser on a much bolder background.

 

As far as changing filters at the unit, or even cleaning the core itself, so far it’s been a trouble-free experience.

 

 

Here’s a photo of a supply-side filter after one month of exposure in winter:

 

zehnder supply filter

A Zehnder supply-side filter (MERV 13) after 1 month in winter.

 

During the summer, of course, they look much worse after a month with so much more “stuff” floating around (e.g. pollen, debris from landscaping, insects, etc.). Also unsurprisingly, the exhaust-side filter always takes much longer to get dirty as stale air makes its way out of the structure (it probably helps that we don’t have any cats or dogs).

 

 

And since we didn’t need the framed-out HVAC chase in the corner of our Master Bath for all the ComfoTubes that we initially planned to send up into our ceilings, we ended up using this area for some much needed niche shelving for various toiletries and even some towels.

Overall, then, we’ve been extremely happy with our Zehnder ERV unit.

 

Windows, Doors, and Suntuitive (Air Sealing #8)

0

Window Options For a Passive House, or a Pretty Good House

Even in 2017, when the majority of our build was completed, the number of Passive House quality window and door options was increasing. Today, in 2018, they’ve only continued to grow.

For example, here is an article from the Green Building Advisor website from June, 2018 discussing high-performance window options: What Windows Should I Buy?

In addition, 475 High Performance Building Supply is selling an Austrian high-performance window, Bewiso:

 

 

A New Jersey Passive House builder, Darren Macri, has created his own product line: Wythe Windows

And GO Logic is an importer of a German brand: Kneer Sud Fenstern und Turen

 

 

They have an old blog post on their site discussing their history with the brand: GO Logic

There are also some custom, small-scale, American-made options as well:

Hammer and Hand

HH Windows

They share similar characteristics, including insulated triple pane glass, thermally broken sashes and frames, multi-point locking systems for airtight seals against gaskets on the frames, the European-style tilt-turn function, and the seemingly ubiquitous but beautiful Roto hardware.

It’s nice to see that more options are becoming available to those looking for high-performance windows in the US — hopefully this means a long-term movement towards better overall building standards in terms of quality, durability, and performance.

And here’s a quick overview on high-performance builds and the need for quality windows and doors: Hammer and Hand

Although not everyone is entirely convinced, and there’s still debate regarding exactly what’s “necessary” in terms of performance (the exception would be building to the Passive House standard, either PHIUS or PHI, where the requirements are more black and white). There’s a lot more latitude if building a Pretty Good House, or the homeowner is only looking to meet the benchmark of Net Zero.

 

 

Suntuitive Dynamic Glass for Our West-Facing Windows

When my wife’s cousin found out we were trying to build a high-performance new home (a mix of Passive House and Pretty Good House), he suggested we incorporate his company’s self-tinting glass. Used largely in commercial applications since its introduction, the product is beginning to make inroads into the residential market as the cost comes down: Suntuitive

For anyone near the northwest suburbs of Chicago, you can see the glass in person at the Ziegler Maserati dealership in Schaumburg, Illinois: Exterior View

As the product has continued to evolve, they’ve been able to remove much of the “green” look to the glass. This is evident in the Ziegler dealership glass, but even in that application I didn’t think that it was all that prominent. The overall look of the glass was still impressive.

As to function, the Suntuitive coating between the layers of glass adjusts its level of tint based on the temperature of an inner layer. In the summer, this has obvious benefits when high temperatures combine with glaring sun to enter a structure, particularly in the east in the morning or the west in the afternoon (even to the south without some protection with overhangs). But the really nice thing about the product is that it doesn’t tint on the coldest days in winter, allowing for some solar heat gain and natural daylight exactly when you want it most on sunny, wintry days.

For energy reasons, and also personal aesthetic choices, we decided to forego any windows on the east side of our house. Instead, we just have our front door facing the street (it has a limited amount of privacy glass to let in some morning light). On the other hand, because we wanted to use a significant amount of glass on the west side, which faces our backyard, and we knew overhangs couldn’t offer much relief from the summer afternoon sun, Suntuitive was a great solution for us — especially since we wanted to avoid using blinds or curtains as much as possible.

Following Passive House principles for glazing, we wanted to optimize our views and connection to the outside through our limited and strategically placed number of windows.

Here’s a useful video showing the effects the sun can have on a structure in various seasons:

 

 

And here’s an interesting video discussing the challenges associated with managing both solar orientation and scenic views when they’re in conflict:

 

 

For our house, we only have a single window to the north (for my daughter’s bedroom), while the majority of our windows are on the south side, where we spend most of our time in the living spaces (open kitchen and family room). In effect, we’ve limited our windows in private areas of the house, mainly two bathrooms. Besides energy concerns, we didn’t think it made sense to add additional glass to our north, mainly because our neighbor’s house blocks any meaningful views while also reducing privacy.

Additionally, we have a significant overhang on the south side, which allows us to block out most of the summer sun while allowing in plenty of winter sun for passive solar heating during our coldest months, so the windows on the southern facade easily take care of most of our daylighting needs.

By utilizing the Suntuitive glass on only the west-facing windows (family room and master bedroom) it allows us to maintain our open view of the backyard while avoiding migraine-inducing summer afternoon sun.

Here are the specs for the particular glass we chose to use (they have a wide variety of options, including color variations): Vertical CrystalGray Triple Glaze Performance Sheet – Lee-Whetzel

Although we lose some potential solar heat gain through these windows in winter (compared to the glass in a typical Passive House certified window), we feel it’s more than compensated for by the blocking of hot, bright summer afternoon sun.

Here’s a company video describing the Suntuitive product in real world applications:

 

 

 

Unilux Windows and Doors

My wife’s cousin suggested a couple of options for the Suntuitive glass: Kolbe Windows or Unilux Windows.

We went to see the Kolbe windows in a local showroom, but they didn’t seem impressive. It also didn’t help that the salesperson was dismissive of the product, suggesting that if we were considering Kolbe we should just use Marvin instead (another brand they sold). The salesperson literally had to wander around looking for a sample unit, eventually finding one buried in a corner. We’re not even sure if what we saw represented the full breadth of the Kolbe product line.

At any rate, since Unilux was willing to work with the Suntuitive glazing, it made it easy to go with them rather than trying to convince another Passive House certified window maker that Suntuitive could be compatible with their product line.

[Note: Suntuitive is constantly adding new manufacturers willing to work with their product, so contact them directly if you have a specific brand you’d like to use on your own project.]

After deciding to go with the Unilux windows and doors, we ended up with the following specs:

[Please note: The numbers below were mostly supplied to me by my Unilux window rep. Following up with a Unilux rep on the East Cost, Scott Gibson, from Green Building Advisor, received different information. If you’re contemplating using Unilux, contact your local rep or the company directly in Germany for written confirmation regarding performance numbers — especially if you’re running data through a program like PHPP.]

 

Main Floor Windows (excludes west-facing windows with Suntuitive):

  • Interior wood with aluminum-clad exteriors
  • Glass: Unilux Super-Thermo 3
    • Triple pane with a reported R-ll center of glass
      • R-8 for whole window once frames are included
  • U-factor of 0.18
  • SHGC of 0.53

 

2-Basement Windows:

  • Isostar: interior uPVC with exterior aluminum-clad
  • The same glass as the main floor windows.

 

Two doors:

  • One for our front entry, and one for our kitchen. They both have the R-11 center of glass glazing, with the kitchen door having a significant amount of privacy glass (it faces south), which is really enjoyable on cold days with the sun shining.

 

We chose PVC for the basement windows to save some money, but also because we thought the natural wood finish on a basement window might look out of place — we’re painting the concrete foundation walls, and partially drywalling an office area, but otherwise we’re leaving the basement unfinished (it will look finished for our tastes at any rate).

The total cost for the windows and doors was just over $26,000 (including the Suntuitive for the windows facing west), with the two doors representing almost $10,000 of this total.

In regards to the Suntuitive glass, it is currently selling for roughly $31/sq. ft., depending on specific application requirements. You can contact my wife’s cousin, Dan, at his email address if you have technical questions, or if you’d like to get a quote for your own project: leed@pleotint.com

I don’t believe the Unilux windows and doors are technically certified by PHIUS or PHI, but their performance metrics are close to the necessary requirements, so we were comfortable using them, especially since we had no intention of pursuing official Passive House certification anyway.

 

 

Window Bucks

After firing our two GC’s in February, 2017, we lost a few weeks as we scrambled to cut ties with them while simultaneously lining up new subcontractors to keep the project moving forward.

Once things were back on track, I was able to begin installing the window and door bucks in preparation for the delivery of the eventual windows and doors.

Using 3/4″ CDX exterior plywood, I installed the bucks so they would extend out far enough to meet up with our eventual two layers of 2″ Rockwool Comfortboard 80 and two layers of furring strips for our ventilated rainscreen (vertical and horizontal since most of our charred cedar siding would be oriented vertically).

Here’s how a similar set-up looked on Hammer and Hand’s Madrona House project:

 

 

We decided to go with “innie” windows, so our windows would be placed near the center of our wall assembly to optimize their energy performance. Placing windows near the center of the wall assembly also creates nice shadow lines on the structure throughout the day. Overall, we just really like the way recessed windows look on a house.

Prior to construction, I created a mock wall assembly with a window buck, which proved to be good practice for building the real thing.

 

mock-wall-assembly-w-sealant-in-sun

Mock-up of the wall assembly put together before construction began.

 

Mock wall assembly after practicing with the tapes:

 

mock-wall-assembly-w-tapes

This mock wall assembly gave me the chance to practice applying these tapes before doing it for real on the house.

 

It’s also worth mentioning that it’s important with these tapes to make sure that once applied you go over them, applying pressure, to ensure the adhesive is properly activated. 475 HPBS always included at least one of their blue Pressfix tools in each box of tape that I ordered. The tool is roughly similar to a bondo spreader.

 

pro-clima-pressfix.jpg

Pressfix after heavy use.

 

We were following many of the details in Hammer and Hand’s Madrona House project:

 

 

I watched their videos dozens of times, especially this one, trying to make sure I got all of the details right. Their Best Practices Manual was also invaluable as I kept referring to it throughout the duration of the build (an incredible gift to contractors and self-builders alike who are tackling a high-performance build for the first time).

Once each buck was installed, I went around and used HF Sealant to seal all the gaps, seams, and screw holes in the window and door bucks.

 

BR #2 window buck with HF sealant

First window buck installed.

 

Here’s a close-up of the same window as the HF sealant is being applied:

 

close up of BR #2 with HF sealant

HF Sealant at the transition between the Zip sheathing and the window buck.

 

And here’s a different buck being sealed on the interior surfaces.

 

lwr rgt int wdw buck w: hf sealant

Using HF sealant to seal seams, imperfections, and screw holes in the plywood window bucks.

 

Another view of the buck being sealed up with the HF sealant:

 

int wdw buck w: hf sealant

 

With the bucks installed, I could then begin applying the various air sealing tapes to all the surfaces of the bucks. I decided to use the Pro Clima line of products, available from 475 HPBS, after ordering them and using them to create my mock wall assembly.

The other option would’ve been to use the Siga brand of air sealing tapes, available from Small Planet Supply, or the black Huber Zip sheathing tape.

Although clearly based on my own personal prejudice rather than scientific evidence, I was reluctant to use the Zip tape, 3M tape, or something similar, mainly because I knew the European brands have a much longer track record of success.

Yet another option would’ve been to use liquid applied membranes (e.g., Prosoco, again Zip, or others), which I’ll address later, when noting the details for sealing up my front door buck area.

Knowing that corners and other areas where elements meet up could be problematic for proper air sealing, as pointed out by Sam Hagerman in this Hammer and Hand video:

 

 

I started by addressing some of these areas first. For example, here’s the lower right of a window buck where it meets the Zip sheathing:

 

lowr rgt buck 1st profil at zip

 

By building up the corners in this way I was hoping to guarantee complete coverage against air and water infiltration at these tricky points.

 

lower rgt buck w: profil at zip

Same area with overlapping top layer.

 

Here’s the top of the buck where it meets up with the Zip sheathing:

 

profil on buck meeting zip

Corner where the buck meets the Zip protected again with 2 separate overlapping pieces of tape.

 

The Profil tape, which splits into thirds on the back, makes corners much easier to tackle.

After using the Tescon Vana in the upper inside corner of the buck, I used the Profil tape to address the upper outside corners of the bucks.

 

int buck w: tvana and 1st profil

Tescon Vana, then Profil for this upper outside corner.

 

Here’s two views of the second top piece for this area:

 

outside upper rgt w: profil

Putting it in place before making a small cut to fold over the outside edge.

 

Here’s another view of the same area, this time looking at the buck head-on:

 

upper rgt of wdw buck w: profil

Same area after cutting the piece and ready to fold it down into position.

 

By making small cuts in the Profil tape with a razor blade, corners are easy to shape to the form you need. Although making a cut while the tape is already in position is relatively easy to do, avoiding any damage to underlying layers is obviously very important. For this reason, it’s probably safer to make cuts before getting the tape into position.

For instance, an initial cut in the Profil tape:

 

cutting profil for corner

 

And then making a fold to establish the basic shape for an outside corner:

 

cut folded profil for outside corner

 

Once you initially set the tape in its position, gently remove the white backing paper, trying to avoid moving the tape too much, which would change its position or cause wrinkles.

I didn’t use the Profil tape for the two lower outside corners since these areas would eventually get throughly covered by the Extoseal Encors sill pan tape.

Once the corners were taped up, I moved on to the bottom of the buck, using the black Contega Solido Exo tape.

First piece of Contega being applied to the bottom of a buck where it meets the Zip sheathing:

 

contega lower lft corner

 

The same area once the piece of Contega is cut to allow it to partially wrap up the side of the buck.

 

contega under and up side

First piece of Contega being installed.

 

Note the white paper backing that helps to position the Contega exactly where you need it, while also reducing the chances for wrinkles to form (an area for potential air leaks).

The Contega, like the light blue Profil, comes with a 3-part split backing. Although this 3-part backing helps a lot, I still struggled at times to avoid wrinkles with the Contega. The Contega is noticeably thinner than the blue Tescon Vana, which is probably why I found the Tescon Vana much easier to use. In fact, if I had it to do over, I would just use a wider version of the Tescon Vana to replace the Contega.

The nice thing about the wider versions of the Tescon Vana is it also comes with a split back for ease of placement.

 

tescon vana 6 w: split backing

6″ Tescon Vana with split backing.

 

Once an initial piece of Tescon Vana (3″) covered the exposed front outside edge of the plywood, I applied the wider Tescon Vana (6″), before applying the Contega to the Zip – buck – bottom piece of Contega connection, effectively bringing these adjoining areas together.

 

starting contega up lft sde buck

Second piece of Contega going up the side of the window buck.

 

Getting the first third of the Contega attached to the Zip before removing the remaining 2 strips of white paper backing seemed to help get it to sit flat without too many wrinkles.

 

contega up lft sde of buck pulling strip

Removing the smallest of the 3 strips of white paper backing.

 

The Contega was then cut so that it lapped the first piece of Contega on the bottom of the window buck.

And here is the Contega as it ends up on the top of the window buck.

 

close up contega up over top of buck

Corners being covered multiple times: HF sealant, Profil tape, and then Contega tape.

 

Making progress across the top of the window buck, building up the layers in shingle fashion, first with the Tescon Vana on the exposed front edge of the plywood, then moving up with the Contega, before finishing with a final strip of Tescon Vana on the Zip sheathing.

 

progressing across top of buck

Moving across the top of the window buck.

 

Top of the window buck almost complete:

 

upper lft buck w: top pce of contega

 

Same area finished off with a strip of Tescon Vana:

 

head of wdw buck finished w: t vana

 

Here’s a side view of a completed window buck. Note the sloped top, achieved with a piece of beveled cedar siding. Hopefully water won’t make its way to this area above each window or door (it’ll have to get past 4″ of Rockwool), but the slope that’s present will hopefully encourage any water that does so to harmlessly drip off rather than hang around to cause potential damage.

 

prepped wdw buck w: sloped top

 

Once the exterior of the window bucks were complete, I went inside to cover the interior head and legs of each buck.

 

contega interior of buck

Contega on the top and sides of the interior of each buck.

 

Here’s a Siga video I only recently came across, showing another way to deal with corners:

 

 

The last area to be addressed was the window sills. For this area I used the Extoseal Encors product. It’s vapor-closed, highly pliable, but also thick to prevent any water that ends up on the sill from entering the structure.

 

 

I really enjoyed using the Extoseal Encors, although you do need to avoid thinning it out as you wrap it around outside corners.

The only time I had a problem with it was on my last window buck. Temperatures were rising and I was working in direct sunlight. It was only in the high 60’s, but that was enough to cause some bubbling in the material.

 

extoseal bubble in sun

Some bubbles caused by working in the sun.

 

In my experience, the Extoseal Encors performed at its best the colder it was outside.

 

window buck almost complete

After a second row of overlapping Extoseal Encors on the sill to the interior, this window buck would be complete.

 

 

Door Bucks

Once the window bucks were installed, I could move on to the two door bucks (front entry and side kitchen entry).

 

legs of kitch buck installed

Installing the door buck for the side, kitchen door.

 

Plywood portion of the door buck complete with bottom piece installed:

 

kitch dr buck looking down at plywood

Looking down on completed plywood door buck.

 

Note the small voids in the plywood pictured below. Because of gaps like these, I chose to cover the edge grain of all the plywood window and door bucks with the HF sealant before applying tapes, just to ensure no air could migrate through the layers of plywood.

 

lwr rgt door buck w: plywood

Outside corner of door buck.

 

After completing the plywood door buck, it was time to give it support from underneath. Although about 2/3 of the door would rest on the subfloor/floor joists, leaving that remaining 1/3 unsupported made me nervous.

While there’s plenty of information available regarding the use of window bucks, I found surprisingly little regarding the installation and weather-proofing of door bucks. I couldn’t find any information for this detail in my Passive House books, or any description of it online, so I consulted with a local GC to come up with a solution.

As an aside, Rick, from Cypress Builders in Palatine, Illinois, proved to be an invaluable resource for a whole host of design problems and issues during our build. After firing our two GC’s, he was kind enough to take on the role of building consultant: Every couple of weeks I would come up with a list of questions, and he would stop by the job site to run through answers and possible solutions.

To his credit, the level of detail involved in a Passive House build didn’t scare him off — it did for many of the other GC’s, carpenters, and siding companies I had out to the job site for estimates — none more blunt than one particular carpenter who could only shake his head over and over as I went through the components of our wall assembly before finally blurting out in frustration: “Why the fuck would anybody build this way”. It’s funny now, but it wasn’t at the time when I was struggling to line up subcontractors in order to try and finish the project.

Rick was incredibly generous with his time, knowledge, and experience — it’s no overstatement to say it’s doubtful we would’ve completed our build without him. His decades in the building industry allowed him to offer sage advice, and I always ended up calmer and more confident about completing the next stage of the build after each of his site visits. I would definitely recommend him to anyone in the Chicago suburbs looking to build or remodel (the mix of experience, honesty, and excellent communication skills is hard to find).

And for any other DIY self-builds, I can’t recommend strongly enough how important it is to look for a similar mentor for your own project. Even if things are going well, whether in the design stage or even the actual build, it can’t hurt to have a construction veteran stop by and try to spot problems, or potential problems. A second set of eyes, eyes that have seen decades of construction acumen along with plenty of stupidity, can only improve the quality of your own build. As invaluable as online resources like GBA, BSC, and Hammer and Hand have been to our build, none of those resources could visit our job site directly, so someone like Rick helped to complete the circle of advice and knowledge that can make the difference between a successful build and total disaster.

To try and give the door buck structural support, I first installed a layer of Rockwool against the green Zip sheathing directly underneath the door buck, attaching it initially with some construction adhesive. I was hoping this would act like the foam in an insulated header.

 

rockwool for under door buck

Prepping the Rockwool for the door buck.

 

After the Rockwool (2″ Comfortboard 80), I attached two 2×8’s with eight Headlok screws through the Zip, rim joist, and some of the floor joists as well.

 

 

We would eventually use these screws extensively to attach our first layer of furring strips through two layers of 2″ Rockwool Comfortboard 80 and our Zip sheathing (again, more on this later). I also used their 4 1/2″ screw to correct a couple of window headers that were out of square. With the spider drive, they work incredibly well.

Unfortunately, when installing the two 2×8’s I accidentally compressed the Rockwool slightly, requiring a final layer of 1/4″ plywood. Thankfully I was able to avoid compressing the Rockwool for my front door buck, so the 1/4″ plywood wasn’t necessary.

 

kitch buck w: 1:4 plywood

Layers of support underneath the door buck. The Rockwool is intended to act as a thermal break, much like foam in an insulated header.

 

Another view of the door buck with basic components installed:

 

kitch buck w: plywood installed

Note the visible gap between the bottom of the buck and the Rockwool on the foundation below. This gap was closed with additional pieces of Rockwool cut to fit.

 

Because of the Rockwool, sealing the end grain of the 2×8’s would’ve been difficult with only the tapes, so I first applied the HF Sealant to try and create a monolithic surface:

 

Side Door - built out w: sealant

HF Sealant covering the Rockwool and the end grain of the 2×8’s. Additional Roxul installed between the buck and the Roxul on the exterior of our foundation to close this gap.

 

If I had it to do over, I’d use Prosoco’s Fast Flash since, unlike the HF Sealant, it’s vapor open, so probably a better long-term solution should moisture of any kind find its way to this area. Once the HF Sealant was dry, it was straightforward to apply the Extoseal Encors.

But before applying the Extoseal Encors, I applied the tapes in the same pattern and manner as I did for all the window bucks.

I also added additional layers of Rockwool and a final layer of pink rigid foam to bring everything out to the same plane before installing the Extoseal Encors.

 

taping side of door buck - south side

Applying the tapes to the kitchen door buck.

 

 

lwr rigt kitch buck w: foam and extoseal

Extoseal Encors across the  bottom face of the door buck.

 

Also, in addition to the Extoseal Encors across the face of the pink foam, the concrete sub later applied a layer of EPDM rubber to try and prevent moisture intrusion/damage in this area.

 

lwr lft kitch dr buck w: first row extoseal

Second row of Extoseal Encors, wrapping down over the first.

 

Although the Extoseal Encors looks great when it first goes on, once temperatures rise it becomes gooey in the sun, so it was a challenge to maintain its integrity before the door went in. If I could do it over, I would hold off on installing the Extoseal Encors until the day before, or the morning of, the door’s installation.

 

lower lft kitch dr buck w: extoseal

From outside, looking down on the bottom left corner of the door buck: last piece of Extoseal Encors installed.

 

From outside, a close-up of the right outside corner of the door buck:

 

lower rgt kitch dr buck w: extoseal

Extoseal Encors wrapped around the outside corner of our kitchen door buck.

 

And a view of the completed door buck:

 

kitch door buck w: extoseal installed

Ready for the kitchen door.

 

For the front entry door buck I repeated the same assembly of components (minus the 1/4″ plywood and pink rigid foam), the only major change a switch to Prosoco’s R-Guard series of products; namely their Joint and Seam and Fast Flash, replacing the Pro Clima tapes and HF Sealant.

Before the start of construction, I intended to use the Prosoco products for all the air and water sealing details, but when it looked like construction would happen in the winter of 2016-17 I knew I had to change to tapes since most of them can be applied below 20° F (this includes the HF sealant), while the R-Guard series of products can only be applied in above-freezing temperatures (you’ll want to contact the manufacturers for exact installation directions and requirements).

Since it was August by the time I did the front door buck, I decided to try the Prosoco products just so I could compare them to the European-style tapes I had been using. I was able to find the R-Guard series of products online at World Class Supply.

 

frt dr buck looking down j and seam

Lower left corner of front door buck. Pink Joint and Seam on the bottom, red Fast Flash running up the leg of the door buck.

 

Exterior head and legs of the door buck covered in Joint and Seam and Fast Flash:

 

lft ext side of frt dr buck w: fast flash

 

Upper right corner of the front door buck after applying Joint and Seam and Fast Flash:

 

upper rgt frt dr buck w: fast flash

 

Lower left outside view of the front door buck after Rockwool, 2-2×8’s, Joint and Seam, and Fast Flash have been installed and applied:

 

front door lower left w: fast flash

 

There were a few gaps between the Rockwool and other components around the house where the Joint and Seam seemed to work surprisingly well as a sealant. Even though the Rockwool is fibrous, the Joint and Seam was still able to stick tenaciously — hopefully it continues to work in the long-term.

And here’s a couple more pics of the completed door buck, ready for the front door:

 

front door entry low shot of fast flash

Completed bottom section of front entry door buck.

 

Standing indoors, looking down at the right corner of the front entry door buck:

 

front door entry w: fast flash

Fast Flash around the perimeter of the front door buck.

 

As things turned out, this front door buck would end up exposed to construction foot traffic and the elements for about 4 months. Having a cheap, temporary front door helped to keep most of the rain out, but even so, the Fast Flash held up surprisingly well. Apart from a couple of tiny touch-ups with additional Fast Flash just prior to the front door being installed, there was little damage to the membrane.

And once the house was done, most people when entering or exiting skip the metal flashing and the door’s threshold (the area I was trying to give added support), preferring to step directly from the concrete stoop into the house and onto the tile since it feels more natural, but it’s nice to know that if these areas ever do see serious weight (e.g. moving heavy appliances or furniture) that it’s fully supported.

Just recently I had time to look through William Maclay’s book The New Net Zero, a fantastic resource I would’ve loved to have before and during our build, and I noticed in a diagram on page 343 the use of a (4″ x 4″) piece of fiberglass angle: “… fasten to rim joist to support extension of floor at door opening”.

If I could do it over, I would use the fiberglass angle instead of the two 2×8’s. Last winter we had a cold spell for about two weeks where temperatures stayed in single digits, and although I checked behind my Rockwool in the basement just below my two door openings at the rim joists for any signs of moisture issues and found nothing (luckily), the fiberglass angle seems like a much simpler solution since it’s thermally broken and much smaller than my two 2×8’s, which would’ve meant I could’ve almost completely insulated below the door bucks while also giving this area plenty of long-term structural support.

Of course, consulting a structural engineer or architect wouldn’t hurt either, just to establish exactly what’s required for tackling this area.

For anyone who’s interested, I found the following suppliers for fiberglass angle online:

 

Grainger

 

Strongwell

 

 

Air Sealing Products: Tapes or Liquid Membranes?

In regards to air sealing, I was really impressed with the Pro Clima series of tapes and their HF Sealant. I was equally impressed with the Prosoco R-Guard series of products (Joint and Seam, Fast Flash, and Air Dam).

Because I found the Prosoco series of products slightly easier to use since they’re less fussy to apply, I would choose tapes or liquid membranes based on the weather conditions of the job site: If it’s going to be too cold to use the Prosoco, then I would use the tapes (and the HF Sealant). Otherwise, I’d probably stick to the liquid membranes. I’m guessing the choice typically comes down to personal preference of the installers (apart from weather restrictions), or what the architect specifies on the drawings.

Here are some videos showing various liquid membranes in action:

 

 

And there are now other copy cat products available:

 

 

And 475 HPBS and Pro Clima now offer their own version of a liquid applied membrane:

VISCONN

 

 

 

Completing Air and Water Sealing of the Windows and Doors (Interior)

Our Unilux sales rep was nice enough to arrange for Bob Riggs and his crew to come down from Wisconsin to install all of our windows and doors. After firing our two GC’s, we really didn’t know who to use for the install. Not many contractors in the Chicago area have experience with these type of windows and doors, so it was hardly straightforward to find someone.

We had ordered our windows in September, 2016, we had fired our GC’s in February, 2017, and we were finally able to install our windows June, 2017. It had been a long wait, so we were excited and nervous to watch them go in. Familiar with Germany’s reputation for engineering excellence, it was one of the more exciting aspects of the build.

 

guys putting in kitchen window

Kellum, Tony, Bob Riggs, and his son Brian placing our kitchen window frame.

 

Bob and his crew did a great job for us. We’re lucky and extremely thankful that they were willing to come down to help us out of a jam. And the guys they used from JPK Builders to help them with the install were also extremely professional and easy to work with (more on this below).

As far as installation details, for the most part the guys followed the steps outlined in this Hammer and Hand video, only changing the Tremco illbruck tape for Hannoband 3E tape:

 

 

I chose to go with the Hannoband 3E tape, but there are any number of options for air and water sealing around windows and doors:

 

 

Here’s a video detailing the use of the Hannoband 3E black expanding foam tape, which I purchased from Small Planet Supply:

 

 

The Hannoband tape has some nice characteristics, such as adding some R-value to the gap, it’s water and air tight, but it’s also vapor-open. It’s also easy to work with and install, it performs really well, and using it means not having to fill the gap between window and framing with canned spray foam (prone to failure according to some Passive House designers and builders). Overall, it just seems like an elegant solution for air and water sealing what can otherwise be a difficult gap to deal with.

Here’s a short video from Tremco showing how these expanding black foam tapes work:

 

 

And here’s a photo of the Hannoband 3E, dramatically showing just how much expansion it’s capable of if left unimpeded:

 

Hannoband 3E showing expansion

On the left, Hannoband just cut from the roll of foam tape. On the right, Hannoband after 48 hours of unimpeded expansion.

 

It also comes in different sizes to better match the gap that needs filling.

The photo below was taken shortly after installation, before the foam had a chance to fully expand.

 

upper rgt wdw fr blk foam b4 expanding

Upper right corner of a window with the Hannoband 3E tape.

 

Here’s a similar corner after the foam has had time to completely expand. The HF Sealant in the corner is just added insurance against air leaks.

 

upper left int wdw frame w: blk foam

Hannoband 3E tape fully expanded.

 

It was pretty impressive to see gaps like this on the day of installation:

 

hannoband-tape-before-full-expansion.jpg

Daylight coming in right after the installation.

 

Only to come back the next day to find the gap completely closed by the expanding foam tape:

 

lft side wdw frame gap filled w: blk foam

The gap is completely closed the next day.

 

I put the Hannoband on ice the morning of the installation since the cold is said to slow down the rate of expansion, giving installers plenty of time to set windows and doors.

A closer view of the Hannoband 3E tape fully expanded between the window buck on the left, and the window frame on the right:

 

lft side of frame close up blk foam

 

A closer view of the upper left corner of one of the windows after the Hannoband has had a chance to fully expand:

 

upper left corner of window w: Hanno tape and HF but before Profil

 

The tapes aren’t cheap, but I thought they were worth every penny.

For the bottom of the window, it wasn’t really clear if the Hannoband tape was appropriate for this area, so I followed Hammer and Hand’s lead, using backer rod to fill the bottom gap before applying HF Sealant (instead of Air Dam like in their video).

 

bottom of int wdw frame w: backer rod

Backer rod being installed into the bottom gap under the window from inside.

 

Lower left corner of the window after the Hannoband tape, backer rod, and HF sealant have been installed.

 

lower lft int wdw frame w: dab of HF

Interior lower left corner of a window after the Hannoband tape, but before the Profil tape has been applied. 

 

Later, for the basement windows, when I had the Prosoco R-Guard series of products on hand, I completely sealed the interior side of the two windows with the Air Dam product, which worked really well. I also used the Air Dam to seal the connection between my basement slab – rigid foam – and foundation walls. It worked really well in that application as well.

 

lower ft int base wdw installed

Basement window before the white Air Dam has been applied between the buck and the window frame.

 

Once the Hannoband tape had a chance to completely expand (roughly 48 hours), I proceeded to tape the perimeter of the windows and kitchen door, both from the interior and the exterior. This included the exterior sills (a common air sealing technique for European windows; considered a big no-no for American-style windows).

Unfortunately, when I was outside, before applying the Profil tape across the bottom of each window, I forgot to stuff in some Roxul Comfortboard 80 (as suggested in the Hammer and Hand video above). I only realized this misstep after reviewing photos for this blog post. Worried about potential negative consequences, I asked a question on the Q&A section of GBA, and I also contacted Floris at 475 HPBS. Although this roughly 1/8″ tall gap is an unnecessary thermal bridge (thanks to my mistake), it shouldn’t impact the long-term durability of the windows or the bucks.

I rented a FLIR thermal imaging camera to check this area, and to just see how the overall structure of the house has turned out in terms of air sealing and insulation (we moved in this past Spring, 2018). Unsurprisingly, the space between the window frames and the bucks/drywall is one of the weakest areas on the entire house. Fortunately, the sills don’t show up any colder than the rest of the frame (I’ll delve more into this in a later post, including some FLIR images from around the house, after detailing the installation of our exterior insulation and siding).

For the front door, we held off on installing it until later in the build in order to protect it from the construction process as much as possible.

 

close up lower lft wdw finished w: HF sealant

Interior view of the gap between buck and window frame taped with Pro Clima Profil tape.

 

Using the Profil tape for this made the process a lot easier. With its 3-part split backing, I could use the narrowest section on the window frame. It was important not to get too much tape on the frame in order to avoid interfering with final trim details (in our case, drywall returns).

On the exterior I tried using the Tescon Vana initially, thinking the gap was wide enough between frame and buck, but the Profil tape was simply much easier to use in tight spaces.

 

rgt side ext wdw frame finished w: tvana

Left to right: exterior gray window frame, Tescon Vana, and tape-covered window buck.

 

I added a little HF Sealant to all the corners just for added protection against air leaks and water intrusion.

 

taping ext of family rm window frame

Applying the Profil tape to an exterior frame.

 

From the outside in we had Profil tape, the Hannoband tape, and then another layer of Profil tape on the interior. Doing it this way involved some time and money, but I thought it was worth it to protect against air and water infiltration for the long-term. I would also only have one chance to get these details right, so some added redundancy also meant added peace of mind.

 

upper lft int buck corner finished w: hf sealant

Another view of a window completely taped and sealed in an upper left corner.

 

I also addressed the brackets on the top of the windows with a mix of HF sealant and tape after the Hannoband had fully expanded:

 

clip above window before Profil #2

First HF sealant applied around the bracket.

 

 

clip above window w: Profil

After the HF sealant, the Profil tape is applied.

 

 

Over-insulating High-Performance Window Frames

When the window bucks were made air and water tight, I took the advice of Hammer and Hand and over-insulated the exterior frames with rigid foam:

 

 

I wanted to use Roxul for this application, but it would’ve taken too much time to order and deliver to site (roughly 2 weeks), and the foam was frankly cheaper and readily available at Home Depot. We tried to go “foam-free” as much as possible, but this was an area where we made a compromise — insulated headers and the gap between our basement slab and foundation walls were the two other areas where rigid foam was used to any great extent.

The exterior aluminum cladding had been held back 1″ from the edge of the wood window frame, allowing me to install 1.5″ of foam between the edge of the aluminum cladding and the window buck (the 1/2″ gap around the perimeter of the window buck opening allowing for proper placement of each window).

 

over insulated frames

Over-insulating the window frame.

 

For the most part this went well, but there were some areas where the interior 1/2″ thick piece of foam did overlap the aluminum frame slightly. As Speier points out in the video, this probably short circuits the intended thermal break somewhat, but by how much I don’t really know (hopefully not entirely).

Also, even if over-insulating the window frames is executed perfectly, it still leaves the window bucks themselves as thermal bridges. I’m sure these show up in the PHPP (the Passive House Planning Package) used for energy modeling, but I’m guessing the energy penalty is slight.

Instead of using 3/4″ plywood or 2x framing lumber to create window bucks, some builders, trying to avoid this area of thermal bridging, have used Thermalbucks as an alternative, but depending on the thickness of the wall assembly there may be limits to their use.

 

 

Another view of the over-insulated frame:

 

lower lft wdw buck w: foam on frame

 

I’ll add additional photos of the windows and doors to a later blog post discussing exterior insulation, the ventilated rainscreen, flashing details, and our siding.

 

kitch dr from int w: sun

Kitchen door installed.

 

 

Issues Arise with our Unilux Sales Representative

The biggest disappointment regarding our new windows and doors was the behavior of our Unilux sales rep.

For instance, when Riggs and his crew were ready to set the first window in place we realized the integrated window sills were going to be way too short (the Unilux sills ship separately and need to be screwed to the front of each window unit). Our Unilux rep immediately suggested moving the windows farther out, near the outside edge of the bucks, in order to make these shorter sills work.

There are a couple of reasons why this was infuriating. First, and most importantly, it would’ve undermined the integrity of the windows since they would’ve been resting solely on the 3/4″ plywood window bucks, rather than the 2×6 framing (the units were heavy, especially our family room and master bedroom windows, which were each 9′ wide and 4′ tall). Secondly, his suggestion immediately told me he had not bothered to look at the construction drawings and Hammer and Hand videos I had emailed to him so he could order the proper sized sills and better understand the wall assembly the windows were going into. The drawings clearly note the proper placement for the windows, and I had explicitly noted this desired mid-wall position in an email.

Luckily, before I could say anything, Tony, one of the carpenters, spoke up and pointed out that the windows needed to be screwed into the 2×6 framing members. I can’t tell you how grateful I was that he had the courage to speak up (in my experience, most people wouldn’t).

The guys also pointed out that I could have custom sills made and then installed during the siding process. Not the end of the world. Sounds good.

 

suntuitive in crate

Suntuitive glass delivered in a crate. For our application it needed to be installed into two empty Unilux frames on site.

 

Later, our Unilux rep was leading Riggs and the guys through the process of installing the Suntuitive glass in the empty west-facing window frames. The guys seemed visibly nervous, and understandably so, as our Unilux rep led them through the process for the first time.

Once the Suntuitive glass was installed, the guys broke for lunch. The Unilux rep then pointed out to me when we were alone that of the 6 pieces of glass 4 of them had the Suntuitive glass logo installed upside down. He shrugged and smirked, perhaps suggesting that it was the carpenters’ fault, or that it was no big deal.

Fair enough, I guess, since it doesn’t impact performance but boy, does it look dumb.

 

Suntuitive upside down

 

Instead of taking a few extra seconds with each piece of glass to make sure that it had the proper orientation, our Unilux rep either forgot to do this, or he just didn’t care. It was hardly the carpenters’ fault since they had never installed Suntuitive glass before.

Still later in the day, when it came time to start installing handles, rather than having what I had ordered on site, our Unilux rep had a cardboard box filled with random handles of various styles: “Is this yours?” “No.” “Is this one yours?” “No.” He only had 2 of the correct handles out of 9. At the very least, this gave the impression that our Unilux rep was disorganized. It turned out he was missing all of the drip caps as well.

Near the end of the first day of installation the guys started installing the kitchen door. Once in place, our Unilux rep went to install the lockset. Something went wrong. He struggled for what seemed like an hour (it may have only been 20 minutes) to get it installed properly. Once he had it installed, he turned and began telling me I would need to remove it to file some parts down to improve the action. For a second time, Tony immediately spoke up, telling me explicitly not to do this, to just use it for a couple of months and it would be fine — which is exactly what happened.

With just my daughter’s bedroom window and the two basement windows left to install, the guys came back the following morning for a couple of hours to finish up. The Unilux rep showed up the second day, dropping some drip caps and the basement handles on a table for me to install. This annoyed me since I had never installed either, and it would’ve taken the Unilux rep a few minutes to do it himself while the guys were working.

And then later, as everyone was leaving, our Unilux rep suggested now that I had seen the guys install the kitchen door surely I’d be fine installing the front door on my own (these Passive House doors are heavy, and ideally require 2-3 guys to install them safely — and preferably by someone who has done it before). They’re also expensive, as I noted earlier, so why would I even contemplate installing it on my own. For a third time Tony probably saw a look of terror on my face, immediately spoke up, and offered to come back to install the front door once we were ready for it.

By chance, Tony somehow managed to be standing next to me each time our Unilux rep made an asinine suggestion. I can’t put into words how grateful I am that Tony spoke up for me and, really, the integrity of our build — he certainly didn’t have to, which probably tells you all you need to know about the quality of his character.

Happy to just have all my windows and kitchen door in, and knowing that Riggs and the  guys were willing to come back to install the front door, I said nothing to our Unilux rep about his behavior.

Later that week, however, we received the Unilux rep’s final invoice. It showed that he was double billing us for job site delivery. It was for just over $300. Not the end of the world, and an easy fix, but, nevertheless, annoying since it seemed to suggest he sent us a final invoice without consulting the original contract.

The invoice also had a storage fee for $1500. He had mentioned months before in an earlier email, after we had just fired our two GC’s, that storage fees were a possibility. At that time we had a lot going on, so I didn’t consult the contract we had signed with him. I just assumed storage fees were in the details of the contract, so when I got the final invoice I planned to pay for it.

But then my wife’s cousin found out about the storage fees, and he expressed surprise, telling us that, in his opinion, no one in the industry does this.

So I went back and looked at the contract. Not a word about potential storage fees. Nothing about when storage fees would begin to accrue, and no fee schedule noting how much per day, week, or month. In an industry plagued by delays, if storage fees were a legitimate billable cost shouldn’t our Unilux rep have the details outlined in his contract?

So then I separately asked a couple of people who work in the construction industry about our situation, one with over 30 years in residential work, the other with over 20 years in commercial construction. They, unsurprisingly, had similar responses:

“What’s in the contract?”

“Nothing.”

“Well, then…”

The one who works in commercial construction was much more blunt:

“So it’s bullshit. He made it up.”

My wife wrote an email to our Unilux rep asking about the double billing for job site delivery and the storage fees, and expressing frustration with how he behaved on the job site during the installation. He responded with a series of emails that can best be described as unhinged or histrionic.

We contacted people above our Unilux rep to see if someone else could come back to finish things up — in addition to installing the front door, a piece of glass broke during installation (we think it was a manufacturing error in the glass), and a different subcontractor broke a part on a basement window that needed to be replaced. They told us our rep was the only one available in the Chicago area, probably, in part I’m guessing, because they wanted our Unilux rep to resolve the situation. Unfortunately, that didn’t happen.

He came back to the site to see the broken part on the basement window, removing the working stay arm (I assumed to make it easier for him to order the correct part, which was a cylinder on the frame that attached to the stay arm). He also dropped off the rest of the missing drip caps and the rest of our correct handles.

 

broken:missing cylinder on base wdw

Missing cylinder on the frame had been snapped off by a subcontractor.

 

A few months after this, in November, after drywall had started, the Unilux rep came back to install the replacement glass for the broken window, and the part for the basement window. He was visibly angry and petulant, clearly still annoyed that we had complained about him.

 

normal basement window

Here’s our other working basement window for comparison. 

 

When we were in the basement he just handed me the working stay arm that he had removed months earlier, apparently for me to install myself. When I pointed out that he hadn’t given me the part for the frame — the actual part that had been broken and needed replacing — he just stared at the open basement window for a few long seconds before we both realized he had failed to order the correct part.

It had been almost six months since I originally requested the part. Making matters worse, he told me from the outset that the window was unsafe to use until the part had been replaced, so we had never had use of this window since its installation.

He also asked if I had the Unilux owner’s manual. No, I didn’t. He never gave me one. I didn’t know one existed. Why he didn’t give me one the first day of installation back in June, or frankly prior to installation, via email, I’ll never know. Instead, I received the owner’s manual nearly 6 months after the windows had been installed.

The owner’s manual emphasizes how important it is that the windows be opened for at least 30 minutes 3 times a day for “forced ventilation” while drywallers are mudding to ensure no moisture damage occurs to the wood on the windows. If he hadn’t happened to be on site while the drywall guys were present, odds are I never would have received this information, thereby putting the long-term integrity of our windows at risk.

And if there had been damage, then what? Replace the sashes? Replace sashes and frames (the entire window units)? Who would’ve paid for it?

Bob Riggs, his son Brian, and Jason from JPK Builders, came back a few weeks after this to install the front door without our Unilux rep present (I didn’t want him near my house again, I think for obvious reasons). The lockset for the front door was installed without incident. In fact, it happened so quickly I didn’t even see them do it. Clearly there’s nothing inherently difficult about installing Unilux locksets.

We couldn’t be happier with Bob and all the guys he brought to the job site. They work hard, they’re detail-oriented, they’re willing to learn new ideas and techniques, and they have excellent communication skills — not to mention a high level of integrity. We wouldn’t hesitate to recommend Bob or JPK to family or friends. They were a pleasure to have on site, and they were very easy to work with. All of which begs the question: Why doesn’t Unilux recruit someone like Bob to sell and install their windows and doors? He’s used to selling his services anyway, and he has all the necessary construction knowledge to properly install high performance windows and doors. It seems like it would benefit both parties.

A few more months go by, it’s the end of June, 2018, and I still hear nothing about the missing part for my basement window, even though our Unilux rep had assured me in an email back in November, 2017 that he would make sure to order it and send it to me. We couldn’t use the basement window for almost a year at this point.

Reluctant to contact our Unilux rep again, I looked around on GBA and found Hawkeye Windows and Doors out of Iowa who installs Unilux windows. I spoke with Larry Martin, the owner, but it turns out he doesn’t sell Unilux windows anymore. Nevertheless, after I explain my predicament, he’s nice enough to offer to hunt down the same, or similar, Roto hardware part for me.

Within a week or two I have the part in my hand. Think about that for a second. I wasn’t even really his customer. It would’ve been so easy for him to just say no, he can’t help me. Instead, he invested time hunting down this random, miscellaneous part for me. I got better customer service from Larry for a $50 part than I did from our own Unilux rep after ordering a whole house worth of windows and doors. It’s astounding in a way, and what a world of difference from a client’s perspective.

During construction it feels like a miracle when you run across people like Bob Riggs, Tony, or Larry Martin — especially after having to deal with someone like our Unilux rep who needlessly made life difficult for us.

Unfortunately, when I go to install the part, although it could work, I realize it would require drilling new holes in the sash and frame. At that point, I get angry again: Why should I have to drill new holes in a brand new window simply because my Unilux rep is too lazy or incompetent to get me the right part?

I contact a couple of people above our Unilux rep, but I don’t hear back from them right away (one was out of town at the time), so I think I have no choice but to contact our Unilux rep again.

Here’s how our Unilux rep chose to respond to my email, carbon copying me and Eric Murray, the East Coast Regional Manager for Unilux:

“They broke this part after the installation; I had ordered one but then lost it [emphasis added].  According to what you mentioned to me a month ago.  I’ve thought Eric Whetzel was so upset with me after all ( despite all my goodwill , hard work and honesty trying to stay with them in good terms….it has been such an unfortunate experience with these clients; it never happened to me during my entire 30 year career…) I don’t understand why is he still speaking with me if he didn’t want to deal with me again? Anyway, if you did not order this yet, I will have Helmut ship directly to them and done with it”

It’s true, we wanted nothing to do with him, and I think for legitimate reasons. But what’s also true is that after more than a year he still hadn’t gotten me the part for my basement window — either out of malice, incompetence, or some mixture thereof. In addition, he claims to have ordered the part, lost it… and then what? He chose to do nothing? Unbelievable.

After this last email from our Unilux rep, he did, in fact, order the part for me, but when it arrived it turned out to be the wrong part, so it was totally incompatible with my window — wasting everyone’s time yet again.

Eventually, Eric Murray and George Wright from Unilux were nice enough to get me the part that I needed, although I’m sure they have better things to do with their time.

Just as a quick summary regarding our Unilux rep:

  • He ordered window sills with the wrong dimensions (wrong by almost 3″), even though I supplied him with construction drawings so he could get this measurement right. And his proposed solution to this problem ignored our construction drawings and what we were trying to accomplish with an “innie” window placement.
  • He didn’t bring most of the handles we had ordered to site. He never found the missing ones, so he had to re-order them.
  • He didn’t bring the drip caps.
  • He almost broke the lockset to our kitchen door, and then told me to remove it and file parts of it down to improve its action. Tony had to interject and explain why this was inappropriate.
  • He installed most of our Suntuitive glass upside down (4 out of 6 units).
  • He suggested I should install my $5,000 front door on my own.
  • He failed to give me the Unilux window and door owner’s manual, putting the integrity of our windows and doors at risk as drywall was being installed.
  • He tried to double bill us for job site delivery of the windows and doors.
  • He was going to charge us $1,500 for storage fees even though the contract says nothing about potential storage fees.

Obviously some of these items on their own would be no big deal, but when considered together what other conclusion is there but that this person is disorganized and can’t be bothered to get details right (this is the nicest way to interpret his behavior). This seems like an awful lot to get wrong for someone who was on the job site for only a day and a half.

The whole situation is unfortunate, as I explained to George Wright in an email, since we really like our windows and doors. Apart from an adjustment required on our front door and a kitchen window, they’ve been wonderful to live with. They’re beautiful to look at, and they function really well. All of this is undermined by the actions of our Unilux sales rep.

Of all the trades and services we knew we’d have to hire for our build, our Passive House window and door supplier was the last one we expected to have issues develop with customer service.

 

 

Suntuitive Glass Performance

Bob Riggs and the guys installed the windows with the Suntuitive glass at an ideal time of the year (June, 2017), just heading into the hottest and sunniest weeks of the year for us here in the Chicago area. It immediately gave us an opportunity to see what the glass can do, and how it behaves on a daily basis.

 

exterior view of Suntuitive in the evening

Suntuitive installed for our west facade.

 

It took a couple of days to get used to the colored tint, but we don’t even notice it anymore. It’s a subtle, beautiful gray that goes well with our charred cedar siding (more on that later).

We quickly realized how well the glass works in direct summer sunlight. The picture above doesn’t really tell you much, but in the picture below you can see just how deep the tinting gets when someone who’s standing in the middle of the window puts their arm out of an open side window. The Suntuitive glass really is like sunglasses for a structure.

 

suntuitive hand in open window

The Suntutive glass almost looks black from the outside when the sunlight is hitting it directly.

 

And even when it’s at its darkest, it doesn’t take long for it to go clear once the sun begins to set:

 

Suntuitive at sunset as tint fades

Evening, and the Suntuitive glass is going clear before nightfall.

 

And you get a real sense of just how effective the tinting is when you stand inside and look out between a picture window and an open window:

 

side by side suntuitive and sun

Side by side comparison: Suntuitive vs. direct sunlight.

 

Here are some more photos of the Suntuitive looking out from the interior:

 

Suntuitive at full tint in afternoon looking out Family Rm window

 

Even in the hottest sunlight, the interior side of the glass only warms slightly. It’s a really impressive product.

 

Suntuitive MBR-Family Rm at full tint in afternoon

 

Another view of the Suntuitive going clear in the evening:

 

Suntuitive at sunset looking into backyard

Suntuitive later in the evening, as it turns clear.

 

In the picture below you can see the glass beginning to tint even though the sun hasn’t quite made it into the backyard to hit the Suntuitive directly from the west. Because the tinting isn’t automatic, its effect is subtle and feels natural as it changes.

 

me taping family rm wdw from int

Suntuitive glass starting to tint.

 

With most of the windows and doors installed, I could start thinking about installing my ERV and ductless mini-split system, planning for my first blower door test, and scheduling the install of our siding.

It felt like a really big step in the build — and it meant no more blue tarps covering the window openings to keep the rain out.

Although the days were long, it helped having my wife and daughter on the job site all the time. It also gave my daughter a once in a lifetime chance to play on an active construction site, and she had a blast.

 

John Ford - beast running away

 A John Ford “Searchers” shot of the Beast running off to play.

 

It’s been fun to mark progress in the build through photos. In fact, looking through photos sometimes produces real surprises:

 

beast-looking-at-view-from-br-for-1st-time-close-up

In late January, 2017, looking out the rough opening for her bedroom window…

 

 

looking out beast's br window for 1st time

Same opening in June, 2017. A really big moment in the build: getting their first look out of my daughter’s bedroom window.

 

Six months had gone by, and we had already survived a lot, with much more to come.

 

Attic Access Hatch (Air Sealing #7 )

0

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 )

2

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, from Chicago Electric, 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 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 side 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 life saver 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, being 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 later 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, 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 final 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 air tight structure.

 

Ceiling Details (Air Sealing #4)

0

Installing Intello

We thought about using the Zip sheathing as our air barrier on the ceiling, attaching it to the bottom of the roof trusses, something I had seen on other builds, but after learning about Intello we decided to use that instead:

 

 

Floris Keverling Buisman, from 475 High Performance Buidling Supply, did our WUFI analysis for us, and he suggested the Intello would be a better fit for our project. The Intello is a smart vapor retarder, so it can expand and contract when it’s needed, and it’s obviously less physically demanding to install than the Zip sheathing.

Once the air sealing was complete around the top of our outside perimeter walls, and the insulation chutes had been installed, we were almost ready for the Intello. At the gable ends of the house, one last detail needed to be put in place, circled in red in the picture below:

 

2x6 on its side

2×6 on its side, circled in red.

 

By adding this 2×6 on its side, which is in the same plane as the bottom of the roof trusses, it makes it possible to carry the Intello over the transition from the ceiling (under the roof trusses) to the walls (top plates). This is one of those details that is hard to ‘see’ when in the planning, more abstract, and two dimensional phase of designing a structure.

 

another angle of 2x6 on side

Another view of the 2×6 lying flat in the same plane as the bottom of the roof truss (far left).

 

Once the trusses were placed on the top of the walls and you start imagining how the Intello will be attached to the ceiling, it becomes much more obvious that something in this space at the gable ends of the house is needed in order to accomplish the transition from the ceiling to the walls.

 

long view w wdw to front door framing

Marking progress: Ceiling ready for the Intello.

 

After reading about so many other projects that utilized Intello, it was exciting to unwrap the first box.

 

unwrapping first box of Intello

Big day: opening the first box of Intello.

 

The directions are pretty straightforward, and the product is relatively easy to install as long as you don’t have to do it alone.

 

Intello instructions

Reading through the instructions one last time before starting.

 

I didn’t get a chance to touch and feel the product before ordering (always fun to do with any new product), so here are some close-ups of the Intello to give you some sense of what it’s like:

 

Intello close up front side 2

Front: shiny side of the Intello — this side will be facing the living space.

 

I was curious about its strength and tried to tear it with various objects, including the cut ends of 2×4’s and the brackets we eventually used to help establish our service core. The material is surprisingly tear resistant, but a utility knife, or a stray sharp edge will cut through it (as our first plumber proved to me with his careless actions — a story for another post).

 

close up Intello back side

Back: matte side of the Intello — this side will be facing the attic.

 

Having never used the Intello before, I decided to start small and began by experimenting with it in a corner. Getting the corners fully covered while getting the material to sit flat before applying the blue Tescon Vana tape proved to be the most challenging part of using the Intello.

 

experimenting w: Intello in corner w: chutes above

Starting in a corner to get a feel for how the material will work.

 

Here’s two more pictures of the flat 2×6 helping to make the transition from the ceiling to the wall on the gable ends of the house:

 

 

In order to attach the Intello to the bottom of the roof trusses, we used the staple gun shown below. Loading it is kind of counter-intuitive (online reviews complain about it not working out of the box, but my guess is — like me — they were trying to load it improperly), but once I figured it out, it ended up working really well, almost never jamming, and it’s very comfortable to hold because it’s so light weight. It should work with any standard air compressor. It was available on Amazon, and in Menards, a local big box store here in the Chicago suburbs.

 

staple gun

The staple gun we used to attach the Intello to the underside of the roof trusses.

 

Think you know how to load it?

 

side view of open staple gun

Staple gun ready for loading.

 

Guess again.

Instead of loading from the bottom, like all the finish nailers I’ve ever used, the staples load higher up, where the staples exit. And yes, there was quite a bit of swearing as I made the transition from “What the…” to “Ohhhh, now I get it…”.

It didn’t help that there were virtually no instructions on its use, apart from a tiny black sticker with an arrow pointing to where to load it (which, of course, I only noticed after figuring this out).

 

staple gun open w: staples

Loading the staple gun.

 

We started with these staples:

 

close up Arrow staples

 

But we ended up going with these instead:

 

close up heavy duty Arrow staples

 

They seemed to grab better (presumably the sharp ends make a difference), and they sit flatter on a more consistent basis (less time having to go back, or stop, to hammer home proud staples flat).

 

stapling Intello to ceiling

 

As we rolled out the Intello, it took some practice to get it to sit taught and flat before stapling.

The dotted lines near the edges of the Intello help you keep the rows straight as you overlap two sheets and progress from one row to the next. The lines also make it easier to maintain a straight line with the Tescon Vana tape (don’t ask me when I realized this latter detail — too embarrassing to admit).

 

taping Intello along dotted line

Follow the dotted line…

 

We checked our initial row from above in the attic:

 

first row of Intello from attic

View from the attic as the first row is installed.

 

Working our way through the interior walls, especially the bathrooms, was more time consuming and took more effort (I grew to hate those interior bathroom walls — first the Intello, then the service core details described below), but once we were out in the open the Intello was fairly easy to install.

 

Intello covering ceiling, chutes in bg

First three rows of Intello as they approach the basement stairwell. Note the insulation chutes in the b.g. in the attic — they took up so much time and effort, and now they slowly disappear (just like most important aspects of infrastructure).

 

 

northwest corner of air sealed attic w: Intello

View of the Intello from a corner of the attic — note the 2×6, far left, lying flat, that helps the Intello transition from the ceiling to the top of the walls.

 

 

Intello from attic at outside corner

Another view of the Intello from the attic after installation.

 

As Eduardo and Jesus rolled out sections of the Intello I followed, pulling on the Intello a little to help make it sit tight and flat before stapling it in place.

 

Eduardo and Jesus helping me put up Intello on ceiling

Eduardo and Jesus giving me a hand installing the Intello.

 

There were a couple of sections, some of the first ones we installed, that I managed to wrinkle (one, in particular, became problematic during our first blower door test — and, of course, it was in a tight spot around the bathroom shower area), but overall, the installation of the Intello went pretty well. Like most things you do for the first time, we got comfortable and good at it just as we were finishing up.

 

Eduardo Jesus and full moon night sky in b.g.

Eduardo and Jesus helping me finish up the main areas as a full moon makes the night sky glow outside in the background. It was a long day (longer still for Eduardo since Jesus was talkin’ trash and nonsense all day — they’re football teammates — needless to say, Eduardo has the patience of a saint).

 

 

Intello from attic w: insulation chutes in bg

View of the Intello from the attic — offering up its 2001: A Space Odyssey glow.

 

After learning about a project on the 475HPBS website…

 

Masonry Retrofit

 

… we decided to use the Tescon Vana tape to cover the staples, as well as all the seams, in the Intello. I have no idea what actual impact covering the staples has on air tightness, but visually as you tape over the staples you can see how, if nothing else, it will help the staples resist pulling out under pressure from the eventual blown-in cellulose in the attic.

Even as the build progresses, it’s interesting how details like this pop up, making building “green” a never-ending process of learning something new — someone’s always coming up with a new product or a new way to do things better, faster, or less complicated — which makes the process itself very exciting.

 

OB applying tape

OB — the Palatine High School legend — the man, the myth, helps me tape over the seams and staples in the Intello. One of the many jobs he’s been kind enough to help me get done. We’d be so far behind schedule without all of his help.

 

 

on plank

View from above what will be the basement stairwell while installing the Intello on the ceiling.

 

 

installing Intello on the ceiling around the basement opening

Almost finished installing the Intello — saved the hardest part for last.

 

This was a nice moment, being able to look back and see the Intello completely installed. It’s almost a shame that we have to cover it with drywall.

 

Intello on ceiling long view

Intello installed and taped.

 

 

2×6 Service Core

A design goal for the ceiling was to keep mechanicals, like HVAC and electric, on the conditioned side of the ceiling air barrier. By doing this, we avoid having to insulate any ductwork for HVAC, or air sealing and insulating around ceiling lights. In effect, we completely isolate the attic, making its sole purpose (apart from ventilating our “cold roof” assembly) holding our blown-in cellulose insulation (this set-up makes it much easier to air seal the ceiling and get the insulation right — at least based on the projects I’ve read about). In order to do this, we created a service chase, or service core, with 2×6’s:

 

service chase w: first couple of 2x6's

First couple of 2×6’s going in.

 

In addition to serving as a space to safely pass mechanicals through, the only other job for the 2×6’s is to hold up the ceiling drywall. The roof trusses, directly above each 2×6, are still carrying the load of the roof and stabilizing the perimeter walls.

 

Simpson L-Bracket w: fasteners

Simpson bracket and fasteners we used to attach the 2×6’s to the underside of the trusses.

 

Here’s what the 2×6’s looked like with their brackets once everything was installed.

 

close up service chase w: bracket-screws

Service core 2×6 with bracket and Simpson SDS bolts.

 

OB and my wife were invaluable as they helped me cut and install all the 2×6’s.

 

 

We installed the brackets first, before raising up each individual 2×6 to fit against the brackets.

 

jesus helping me install 2x6's

Jesus helping me install the 2×6’s.

 

Since the brackets were directly attached and under a roof truss, we were able to keep the 2×6’s fairly straight, even when the board itself was less than perfectly straight.

 

service chase w: just brackets

Brackets installed before the 2×6’s go up.

 

A feisty Robin kept trying to set up a nest on our partition wall (our windows and doors aren’t in yet). Apparently she believed we had created an elaborate bird house just for her. It took almost a week before she finally gave up — but not before starting multiple nests in multiple spots along the wall.

 

bird nest

Robin making one of her many attempts at a nest on our partition wall.

 

Along the outside walls, at the top of the wall assembly, there was a gap that we utilized for maintaining continuous insulation. This meant there will be no break in our thermal layer going from the blown-in cellulose insulation in the attic to the monolithic layer of Roxul Comfortboard 80 (2″ + 2″) that will be on the exterior side of the Zip sheathing.

 

trusses - Intello - Roxul

Adding Roxul at the top of our wall.

 

 

layer of Roxul at top of outside wall

Close-up of the Roxul going in on top of the top plates.

 

 

Intello - Roxul - wall

Another view after the Roxul has been installed.

 

 

long view from west window w: service core complete

Marking further progress: Intello and 2×6’s installed.

 

Once the 2×6’s were up, we had to install our pieces of 1×4 in order to prevent the 24″ of blown-in cellulose that will be going into the attic from causing the Intello to sag.

The plans called for the 1×4’s to be installed right after the Intello, but before the 2×6’s, which would have been a lot easier and quicker, but, unfortunately, the GC’s we fired installed the interior walls too high, making this impossible.

Here’s what it should’ve looked like if we could’ve done Intello and then the 1×4’s (photos courtesy of 475 HPBS) before installing the 2×6 service core:

 

 

Having no choice but to methodically cut each 1×4 to fit between each set of 2×6’s, OB was nice enough to help me get it done.

 

close up of partition wall w: service core and 1x4 cross battens

 

Installing the 1×4’s between the 2×6’s began with some experimentation:

 

service core w: cross battens and L-brackets

Using L-brackets at first —  it proved too time consuming and expensive.

 

After experimenting with a finish nailer (too easy to miss and penetrate the Intello), we eventually settled on Deckmate screws. It was definitely a laborious process, but eventually we got into a rhythm and got it done, although we wouldn’t recommend doing it this way — way too time consuming.

 

ceiling w: 1x4 battens

Completing our service core.

 

We tried to keep the 1×4’s about 16″ apart, which should prevent any significant sagging in the blown-in cellulose from occurring (I’ll post photos once the cellulose has been put in the attic).

A lot of blood, sweat, and tears have gone into completing this house.

Here’s some proof:

 

screw got me

A decking screw got me.

 

In trying to avoid puncturing the Intello, I would hold a couple of fingers on the back side of the 2×6, feeling for any screws that would come through on a bad angle. A couple of times I drove a screw too quickly and paid the price.

 

looking up at Intello and service core from basement

View of the service core from the basement. Installing the 2×6’s and the 1×4’s also required walking the plank a few more times.

 

 

installing ceiling w: OB

OB making my life easier as I work on the plank installing the 1×4’s.

 

 

Maintaining the Intello After Installation

Unfortunately, there was a delay in getting shingles on our roof, due in large part to our first disorganized and incompetent plumber (again, more on this later). Consequently, we were in the awkward position of having our ceiling air barrier and service core all set up but every time it rained we still had a leaking roof. In most areas it wasn’t a big deal, but in about a dozen spots rain would collect and, in some cases, cause a bulge in the Intello as it held up the weight of the captured water. To relieve and ultimately to avoid this pressure, I cut small slits in the Intello where the rain would consistently collect.

 

small hole in Intello for rain before shingles

Slit in the Intello to allow rain water to fall through, marked with a red marker for easy identification later.

 

Once the shingles were finally on, I went back and found all of these slits and taped over them with the Tescon Vana.

 

Tescon Vana covering hole in Intello

Hole in the Intello covered and air sealed with the Tescon Vana tape.

 

We also found a couple of weak spots in the Intello as we installed it, and even later, during the installation of the service core. These spots were marked as well, and they, too, got covered with the Tescon Vana tape just for added insurance against air leakage.

 

imperfection in the Intello marked for Tescon Vana

Weak spot, or imperfection, in the Intello. This got covered with Tescon Vana as well.

 

After having to fire our GC’s, we couldn’t have kept the project going without the help of family and friends. As awful as some aspects of the build have been, it’s been heartwarming to find people willing to help us see the project through to the end (much more on this later).

 

2 Cheshire Cats

Couple of Cheshire cats — clearly up to no good — helping us to keep the job site clean.

 

Framing (Air Sealing #2)

2

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 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:

 

 

More gymnastics required while applying the Contega HF 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 photos 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.