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Passive House + Zero Net Energy + Permaculture Yard

Category Archives: Structure of House

Siding Part 2: Charred Cedar (Shou Sugi Ban)

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Building a Passive House: Science, then Art

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

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

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

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

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

 

 

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

 

South Barrington McMansions Languishing

 

McMansions at Fire-Sale Prices

 

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

 

McMansions No One Wants

 

Killing the McMansion

 

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

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

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

 

 

Massing: Basic Forms

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

 

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

 

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

 

1st layer rockwool at frt door

Wojtek installing Rockwool around the front door, next to the garage.

 

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

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

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

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

 

 

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

 

 

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

 

 

 

Siding Layout for our Charred Cedar (Shou Sugi Ban)

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

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

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

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

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

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

 

 

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

 

sketch black:gray

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

 

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

 

ehb s and w elevations

Proposed siding layout from Evolutionary Home Builders.

 

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

 

brown - brick typical layout

Popular way to break up the cladding on a ranch home, in this case mixing brick and wood.

 

 

brick w: light sd

Another example of the same layout, this time with lighter colored siding.

 

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

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

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

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

 

charred cedar sample board with natural

Sample board with natural and charred cedar.

 

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

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

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

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

 

natural-and-charred-together

“Natural” cedar, treated with tung oil, next to the charred cedar.

 

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

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

 

floating toilet

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

 

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

I guess the situation could’ve been even worse:

 

 

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

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

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

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

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

Cedar Siding Delivered…
Oiling Charred Cedar Siding

 

 

Installing the Charred Cedar

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

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

 

1st pce char going on

Wojtek and Mark installing the first piece of charred cedar on the south side of the garage.

 

 

1st few rows south sd sd gar

Wojtek and Mark making progress on the south side of the garage.

 

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

 

s garage char 1:2 way

First few rows of charred cedar going up on the south side of the garage.

 

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

 

south garage 1st pce east wojtek and mark

Wojtek and Mark starting the east, vertically oriented, side of the garage.

 

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

 

garage south sd start east wojtek and mark

Finally getting to see the combination of horizontal and vertical orientations combined.

 

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

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

 

close up char on garage texture

Close-up of several charred cedar boards.

 

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

 

oil and texture on garage sd

The range of textures and subtle variation in color makes the charred cedar truly unique.

 

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

 

 

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

 

 

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

 

garage sd out front door

View of the garage from the front doorway.

 

 

south gar sd mostly done mark in bg

First look at a large section of the charred cedar siding installed.

 

 

south gar sd bringing you in to frt dr

A second view.

 

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

 

n side garage furring and coravent

North side of the garage prepped and ready for siding.

 

 

1st pce north gar sd

First few pieces going up on the north side of the garage.

 

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

 

Cor-A-Vent PS-400 Box

Box of PS-400 strips for soffit ventilation.

 

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

After looking around online, I ended up finding a product at a local Home Depot.

 

mesh for soffits

Metal mesh product we used for soffit ventilation.

 

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

 

close up soffit screen complete

Close-up of the soffit metal mesh installed.

 

 

outside view n gar soffit

First section of soffit going up with the metal mesh in place for ventilating the roof.

 

 

mark w: gar soffit screen mostly complete

Mark waiting for a cut, with most of the soffit and siding installed on this side of the garage.

 

 

garage soffit w: screen complete

Section of soffit complete with metal mesh installed.

 

 

north garage sd soffit complete

North side complete, with the frieze board finishing off the rainscreen details.

 

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

 

https:::hammerandhand.com:best-practices:manual:4-rain-screens:4-1-top-wall:

Courtesy of Hammer and Hand and their Best Practices Manual.

 

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

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

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

 

wd view top of garage rscreen

Top of the wall is ready for siding, and for establishing the air gap for the wall’s rainscreen.

 

 

mark blocking 4 frieze and vent

Mark adding blocking in preparation for the frieze board to finish off the top of the wall.

 

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

 

wide view garage frieze w: blocking sd

Top of the Cor-A-Vent and the top piece of siding. Frieze board being installed over blocking in the background.

 

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

 

close up rainscreen gap n garage

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

 

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

 

garage south sd start east wojtek and mark

Wojtek and Mark moving across the front of the garage with the charred cedar now oriented vertically.

 

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

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

 

char as garage sd east goes up

Anita starting to burn additional boards as Mark and Wojtek keep working.

 

 

most of east side garage complete

Mark mostly done with the front of the garage.

 

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

 

sd soffit w: frieze for vent gap

Overhang on the front of the garage: frieze board completing the rainscreen, soffit boards, and rake boards being installed.

 

 

garage soffit and rake

Closer view of garage soffit and rake being installed.

 

 

garage side view strapping vent sd

Cut away view of the siding with a rainscreen set-up behind it.

 

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

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

 

outside corner soffit w: tiger stripe

Close-up of the garage soffit at an outside corner.

 

 

nw corner garage start n sd

The guys making the transition from the garage to the north side of the house.

 

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

 

north side char

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

 

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

 

mark at mechanicals

Mark working around the mechanicals on the north side.

 

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

 

 

 

 

Installing the Natural Cedar Accents

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

 

stacks of nat'l and char in garage

Natural cedar boards tung oiled and ready to be installed.

 

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

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

 

west 1st cple pcs nat'l wojtek and mark

 

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

 

west after 1st few nat'l pces

Adding natural boards around the window on the west facade.

 

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

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

 

mark just past nat'l on west

Mark completing the natural accent around the left window.

 

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

 

mark and wojtek west sd after nat'l

Mark approaching the center of the west facade.

 

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

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

 

wojtek burning cut edge

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

 

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

 

lking up sd at west peak

Looking up at the center of the west facade.

 

 

lking up sd at west peak wider view

Wider view of the peak on the west facade.

 

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

 

west facade sd after peak

 

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

 

west sd mostly done guys start south

 

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

 

west facade after sd b4 gutters

West facade mostly complete.

 

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

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

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

 

 

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

 

sd west b4 gutters

Waiting for gutters and downspouts.

 

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

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

 

 

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

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

 

Shelby stripes

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

 

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

 

 

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

 

 

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

 

 

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

 

 

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

 

repsol full

 

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

 

repsol screen saver

Vivid screensaver.

 

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

 

love bug

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

 

Another example of this thick-thin combination:

 

racing strip hash marks wheel

Hash marks on the wheel of a Dodge Charger.

 

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

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

 

 

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

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

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

mark ready for natl at kitch

Mark almost ready for the natural cedar boards.

 

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

 

1st couple at kitch

 

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

 

mark past natl at kitch

Mark and Wojtek moving past the natural cedar boards.

 

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

 

kitch dr

Kitchen door with its charred and natural cedar.

 

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

 

1st pce nat'l at frt dr

Putting up the first piece of natural cedar around the front door.

 

 

mark finishing up nat'l at frt dr

Mark nailing in the first couple of natural boards.

 

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

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

 

mark just after nat'l at frt dr

 

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

 

sd done b4 frt dr

First look at the east facade fully sided. Our little black box almost complete.

 

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

Check out the details of their installation here:

Windows, Doors, and Suntuitive

 

Brian Jason Bob install front door

Brian, Jason, and Bob install our front door.

 

 

frt dr frt yard

Front door just after installation.

 

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

 

 

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

 

frt dr clup b4 trim

Close-up of the front porch just after the door was installed.

 

 

Installing Sill Pans

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

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

 

sill pan inside edge b4 return trim 2nd view

Metal sill pan slid under bottom aluminum edge of the window.

 

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

 

inside corner sill pan b4 return trim

A second view of the same area.

 

 

mbr wdw w: sill pan b4 final pce trim

From inside looking down at the sill pan.

 

 

side view sill pan edge beyond sd

Outside edge of the sill pan.

 

 

south wdw after sd b4 trim

Window waiting for the last few pieces of trim.

 

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

 

k wdw trimmed out fmly rm wdw bg

Kitchen window with all the trim pieces installed.

 

 

innie wdw face - frameless look

Once the screens were installed, there was almost no room to spare. We really like this “frameless” look combined with the “innie” window position — it creates some really nice shadows at various times during the day.

 

 

frt dr sill pan

Front door sill pan installed.

 

 

kitch dr sill pan

Kitchen door with the sill pan installed.

 

 

Wojtek installing first sill pan

Wojtek pulling off the protective plastic on the sill pan.

 

 

mark and wojtek install 1st pce garage roof flashing

Mark and Wojtek installing flashing on the top of our garage roof.

 

 

2nd shed rf flash

Wojtek screwing down the flashing.

 

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

 

mbr wdw frame sill pan

 

 

Gutters and Downspouts

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

 

nordic ne

 

 

nordic n

 

 

Decorative Details

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

Our exterior lights were found on Amazon: Hyperikon

 

house numbers out of storage

‘Wobbly’ house numbers.

 

 

doorbell

Gecko doorbell finally installed.

 

 

house # and drbell

Front door details complete: trim, sill pan, doorbell, house numbers, and exterior light.

 

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

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

 

708 white porcelain w: spax

 

 

Stucco for Inside Window Wells

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

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

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

 

Tomasz

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

 

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

 

stucco 2nd coat k dr

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

 

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

 

wdw wll 3

Gutters going up just after the railings around the window wells were installed.

 

 

wdw wll 2

View of the railing from a basement window.

 

 

How Durable is the Charred Cedar?

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

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

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

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

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

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

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

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

 

north light orange

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

 

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

Here are some pictures showing the extent of the fading:

 

west b4 tar

West facade facing the backyard.

 

 

kitchdr19b4

South side.

 

 

s east end b4 tar

Another view of the south side.

 

 

south garage b4 tar

South side of the garage.

 

 

garage b4 tar

East-facing side of the garage.

 

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

 

close up missing char

Arguably the worst area of fading on the charred cedar.

 

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

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

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

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

 

 

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

 

tiger striping on south overhangs

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

 

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

 

w sw as pine tar being applied

Starting on the west side with the black pine tar.

 

 

pine tar fmly rm wdw - bleached out to rgt

Making progress on the south side.

 

Our little black box with revitalized skin:

 

w after tar evening

West facade complete.

 

 

south west fmly rm after tar

Southwest corner after pine tar.

 

 

south tower after tar

Another view of this southwest corner.

 

 

porch after tar

Front entry and the south side of the garage after pine tar.

 

 

front after tar

Another view of the east facade after the pine tar.

 

 

708 after tar

Closer view of the charred cedar after the pine tar.

 

 

close up char texture after tar

Close-up: the black pine tar had no negative impact on the heavily charred areas.

 

 

after tar still variation color texture

On areas with the lightest char the black pine tar soaked in but didn’t completely make the surface an opaque black. My guess is, a second coat probably would’ve made it opaque.

 

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

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

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

 

Bridgersteel

 

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

 

Still another product worth considering:

 

Thermory USA

 

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

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

 

sd at kitch dr at night

Kitchen door and stoop with the light on.

 

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

 

frt dr w: light

 

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!

Blower Door (Air Sealing #9 )

2

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

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

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

 

 

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

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

 

 

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

 

HF Sealant in corners b4 blower door

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

 

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

 

sealant on wdw components junction

Seam near bottom of window where components meet — sealed with HF Sealant.

 

Where components come together is often an area that needs special or further attention.

 

close up corner and wdw components seam w: sealant

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

 

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

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

 

area of kitchen sill plate leakage

Area of kitchen sill plate leakage.

 

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

 

 

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

 

 

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

 

Steve starting blower door test

Steve setting up the blower door for his first test.

 

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

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

 

Steve testing window gasket

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

 

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

 

Steve showing impact of unlocked window

Steve showing me the impact a window in the unlocked position can have on air tightness. The gasket, ordinarily squeezed in the locked position, works to bring the sash and the frame tightly together.

 

 

Steve smoke at family rm wdw

Looking for areas around the windows that might need adjusting or additional air sealing.

 

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

 

Steve at kitchen door

 

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

 

 

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

 

Steve testing attic hatch

Steve testing the attic hatch for air leaks.

 

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

 

Steve testing plumbing vent in kitchen

Steve testing for air leaks around the kitchen plumbing vent and some conduit.

 

 

Steve testing for air leaks @ radon stack

Steve testing for air leaks around the radon stack.

 

 

Steve @ radon stack close up

Close up of radon stack during smoke test.

 

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

 

Steve testing wrinkled area of Intello

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

 

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

 

Steve testing for air leaks @ main panel

Checking for leaks at the main electrical panel.

 

 

Steve testing for air leaks @ main panel exit point

Checking for leaks at the conduit as it exits the structure.

 

 

Steve testing for air leak @ sump pit cap

Looking for air leakage around the sump pit lid.

 

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

 

Steve testing for air leaks @ ejector pit

Testing the ejector pit for air movement.

 

 

Steve testing for air leaks @ Zehnder exit point

Checking for air leakage around one of the Zehnder ComfoPipes as it exits the structure.

 

 

Steve testing for air leaks @ pvc:refrigerant lines

Looking for air leaks around the heat pump refrigerant lines as they exit the structure.

 

 

Steve smoke at sump discharge

Checking around the penetration for our sump pump discharge to the outside.

 

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

 

ejector pump lid w: duct seal

Ejector pit lid with some duct seal putty.

 

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

 

Final Blower Door Test Results

 

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

 

Steve at front door

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

 

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

Here are the final figures noting where we ended up:

 

0.20 ACH@50 and 106 cfm@50

 

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

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

 

Not Airtight

 

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.

 

Basement Slab (Air Sealing #5)

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The Bottom of our Thermal Envelope

Following Passive House principles, we knew we were going to insulate and air seal our basement slab. As explained on the Passipedia website:

“The most important principle for energy efficient construction is a continuous insulating envelope all around the building… which minimises heat losses like a warm coat. In addition to the insulating envelope, there should also be an airtight layer… as most insulation materials are not airtight. Independently of the construction, materials or building technology, one rule is always applicable: both insulation and airtight layers need to be continuous.”

 

airtightness_with_logo

Illustration courtesy of: passipedia.org

 

The illustration above also shows the “red pen test”, which is supposed to occur in the design phase of a project, when it’s much easier to address weaknesses or errors in the details of a design — not necessarily just for air sealing, it’s also effective when looking for points of potential water intrusion (e.g., this GBA article), or even to test the thermal layer for areas of thermal bridging. The basic idea is that if your layers aren’t continuous you’ll find yourself lifting your red pen, meaning it’s an area that needs to be addressed.

An effective way of thinking about a structure, utilized by high-performance builders, is to think in terms of 6 sides rather than just 4 when contemplating the details for air sealing and insulating: 4 walls, the attic/roof, and the basement (or frost-protected slab).

A similar approach to Passive House for building high-performance structures is adopted by advocates of The Pretty Good House concept, even if it’s less stringent, more open to interpretation, and tends to be more “rule of thumb” rather than energy model driven (e.g. PHPP or WUFI).

Based on our climate region, which is Zone 5, we decided we wanted to shoot for 16/20/40/60 for insulation R-values — the series of numbers represent R-values for under the basement slab/ the exterior foundation walls/ framed exterior walls/ and the attic (our attic R-value proved to be significantly higher than 60, but more on that later) — which is in the ballpark for both PGH and Passive House (here’s an excellent overall summary of the PH concept I recently came across: EcoCor).

Arguably, the “sweet spot” for how much insulation makes sense for these areas, even when adjusted for climate region, is still a topic for heated debate. Nevertheless, it’s important to keep in mind that the more simple the form your structure takes — for example, 2-story cubes without basements —

 

 

the easier it is to achieve Passive House, or similar building standards, since it simplifies framing, air sealing, and limits the exterior surface area in ways that a single story ranch that is spread out and has all kinds of nooks and crannies does not (the difference also has serious ramifications for overall heating and cooling demand). Likewise, simple forms also make it easier to figure out how much insulation you need to reach a benchmark like Passive House or PGH. A simple form can also have durability implications.

Our R-values were based on a number of considerations: the construction drawings of our original builder, information made available by Hammer and Hand (in particular their Madrona House project), and articles on the Building Science Corporation (in particular: 1 and 2) and Green Building Advisor websites. These resources, all of which have proven to be indispensable at every stage of the build, have made our project possible.

In terms of the details around the slab and the foundation walls, this article from the DOE also proved to be especially helpful: Foundation Handbook

 

2-04_no-cap

Illustration courtesy of: foundation handbook.ornl.gov

 

After considering various insulation choices (Wall Assembly), we decided to go with Roxul for under our slab, the exterior of our foundation, and our wall assembly (blown-in cellulose in the attic was the only significant deviation from the use of Roxul).

Here’s how the basement slab portion of our project progressed:

 

 

Roxul Comfortboard 80 (2″ + 2″)

To get to an R-value of 16 we used two layers of 2″ thick Roxul Comfortboard 80 (R-4 per inch).

We installed each layer with staggered seams, although the Roxul representative I spoke with via email insisted that because the Roxul is so dimensionally stable this isn’t nearly as important as it would be with rigid foam insulation (the same holds true with a double layer of Comfortboard 80 on the exterior side of wall sheathing).

 

roxul in basement 2 layers

Putting down the 2 layers of Roxul Comfortboard 80 with help from the concrete guys.

 

 

roxul long view two layers

The second layer of Roxul being installed.

 

 

roxul before stego

Installing the Roxul around the rough-in bathroom pipes, sump, and ejector pits.

 

One of the many benefits of using Roxul is that the material wants to stick to itself, whether in batt or rigid board form. This makes for tighter joints between pieces, and even when cuts around obstructions are less than perfect it’s easy to fill in any gaps with torn apart pieces of Roxul (again, this holds true for both Comfortboard 80 and their version of batt insulation).

 

roxul stuffed in around basement pole

Stuffing bits of Roxul around the base of one of the steel columns.

 

Close up of the Roxul installed around the roughed-in bath PVC pipes.

 

roxul around rough-in bath

 

Another view of the 2-layers, mostly installed.

 

roxul before stego - facing ladder

 

A Roxul rep told me to take into account a loss of R-1 due to the compressive pressure of the poured concrete, thus our R-16 for two layers of Roxul is, according to Roxul, really an R-15. Having installed the two layers myself, walked on it during and after installing the vapor barrier (see below), my guess is in some areas this loss in R-value is even greater than R-1.

Based on the comments quoted in a GBA article (Sub-Slab Mineral Wool), I would have to say my experience was exactly the same: in some areas the Roxul seemed to lose most, if not all, of its rigidity. I’ve also noticed while working with both the Comfortboard 80 and their batts that there seems to be a variation in the material from one piece to another and even bag to bag. Some pieces are very easy to cut (these pieces are noticeably stiffer), while other pieces seem “mushier” or lacking in rigidity — either under or over-cooked perhaps — making them more difficult to cut and work with. This seems like less of an issue for vertical applications (i.e. walls), while potentially troublesome for horizontal applications under a slab — especially if you’re depending on that R-4 per inch to meet the demands of energy modeling for a certification program like Passive House.

I’m glad we’ve been able to mostly avoid foam insulation in the build, but seeing the Roxul in a real world application does make me wonder if some kind of rigid foam might’ve given me a more consistent whole floor R-value. Going with a denser version of Roxul would’ve been another, more expensive, option as well (Comfortboard 110).

 

 

Stego Wrap

Once the two layers of Roxul were down, it was time to install the vapor barrier over the insulation. While the Roxul acts like a blanket, helping to maintain a consistent temperature in the basement, the vapor barrier helps to keep moisture and soil gases (mainly Radon as I understand it), at bay.

The product I’ve seen used in most Passive House, Pretty Good House, or equivalent projects, is Stego Wrap. Here are two videos detailing its installation and its benefits:

 

 

 

 

Another product I came across while researching options was Perminator.

Here’s a video detailing the use of the product:

 

 

In my area — the suburbs of Chicago — the closest supplier of Stego Wrap was HD Supply.

 

starting stego around roug-in pipes

Starting around the rough-in bathroom pipes.

 

We used the 10 mil version of the Stego Wrap. The material is very durable and fairly hard to damage. Even when tears occurred, it was easy to patch with pieces of the Stego red tape, or a combination of a cut piece of Stego Wrap with pieces of the red tape.

 

stego going down

Stego Wrap carried up the wall and taped to keep it in place.

 

Installing the two layers of Roxul on the basement floor was pretty straightforward, while installing the Stego Wrap was generally a pain in the ass. Maybe I was just tired, but I really didn’t enjoy installing it at all. For example, it was difficult to keep it tight to the walls, although I learned to leave it hanging fairly loose at floor-wall junctions, which definitely helped. Getting the first row straight, flat, and smooth was time consuming, and annoying, but it did make getting successive rows installed straight much easier.

 

jesus helping me w: first row stego

Jesus helping me install the first row of Stego Wrap.

 

 

almost halfway w: stego wrap

Making progress with the Stego Wrap.

 

 

sealed basement pipe close up before pour

Stego Wrap wth red Stego tape and a Roflex gasket from 475 HPBS.

 

The pipes after air sealing with EPDM gaskets and red Stego tape:

 

sealed basement pipes with overlapping Stego

 

Once all the Stego was in place, we added a 1/2″ of rigid foam insulation at the floor-wall junction as a thermal break. I wanted to use Roxul Comfortboard 80 (their 1.25″ thick version) even for this, but time (Comfortboard 80 is still a special order item in my area, meaning it’s always about 2 weeks away from the time you place your order — hopefully this changes in the near future) and money made the foam an easier choice.

 

stego w: foam close up

 

We kept the foam in place by running a bead of OSI sealant on the back of each section before pushing it up against the Stego Wrap. For the most part this seemed to work well.

 

stego w: foam at slab edge

Roxul, Stego Wrap, and foam installed.

 

Here’s a close-up of everything installed in a corner:

 

stego w: foam at a corner

 

One of the real disappointments of installing the basement slab was seeing the concrete guys put down the welded wire mesh (typically noted as W.W.M. on construction drawings) — basically chicken wire with pointy ends (I exaggerate, but not by much).

 

 

If I could do it over again, I would look into using a concrete mix containing sufficient pieces of fiberglass, or some other alternative, so that using the welded wire mesh could be avoided altogether.

 

 

 

 

I was already familiar with the idea of fiberglass used in place of metal rebar in concrete forms, having experimented with decorative concrete last year and having seen videos like these:

 

 

 

 

I’m not sure why I didn’t think to ask for fiber reinforced concrete instead of the normal welded wire mesh — it was one detail that just got missed, unfortunately.

As the wire mesh went down, the guys could see how annoyed and concerned I was by the holes it was making in the Stego Wrap that one of them, Oscar, started helping me bend the pointy ends up. Once they were safely pointed up, I went around with the red tape to patch the many tiny holes in the Stego Wrap. Not a fun way to kill a couple of hours.

Why my architect or the concrete guys didn’t suggest a mix with fiberglass instead of the welded wire mesh is unclear. The reality with any green build, especially if you’re acting as GC, is you’re likely to be the only one who really cares about getting the many details right, especially if the architect and subcontractors have never built like this before — they were just doing what they always do.

A couple shots of the basement floor with the welded wire mesh in place:

 

 

A closer view with all the elements in place prior to the pour:

 

corner of basement pre-pour

 

 

Concrete

Here’s various shots of the slab itself being poured:

 

hole in floor for basement slab

It was necessary to cut a hole in the subfloor just inside the front door in order to get the concrete into the basement.

 

 

concrete going thru floor

 

 

long view of brace for pour

The guys starting at the back of the basement.

 

 

leveling back corner of basement

 

 

back corner of basement pour #2

One corner complete.

 

 

pour heading towards basement stairwell

 

 

leveling towards stairwell

 

 

pour at stairwell

 

 

Tools at stairwell

 

 

finishing concrete at stairwell

 

 

troweling at stairwell

Enrique completing the trowel finish.

 

 

cement truck kissing corner of garage

Side of the garage kissed by the cement truck.

 

 

close sewer clean out

Close.

 

 

close long view sewer

Really close.

 

 

Slab Edge

Once the slab was in place, I wasn’t quite sure how to deal with the edge along the perimeter. As usual when I get stuck on some detail, I asked a question on GBA:

 

How do I seal…

 

Stego Wrap and Foam cut away from slab edge

Cutting away the excess Stego Wrap and purple foam.

 

 

close up of slab edge

Close-up of the wall-slab junction after cutting everything down flush with the floor.

 

Using the Prosoco Air Dam seemed like the best, and most straightforward, option. In addition, after considering various ways to cover this gap after the Air Dam was down between the wall and floor, and after priming and painting the basement walls, I realized the gap visually disappears for the most part, and really wasn’t worth thinking about.

 

wall-slab connection after air dam.jpg

Junction between wall and slab after using Air Dam and priming and painting the wall.

 

 

close up of wall - slab conection after air dam

Close-up of Air Dam, after primer and paint, at the wall-slab connection.

 

 

another view slab:wall connection

Another view of the slab – wall connection.

 

By not putting anything down to cover this gap, if the basement ever does experience water damage, it’s one less thing to remove and replace.

Ceiling Details (Air Sealing #4)

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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.

 

Insulation Baffles vs. Insulation Chutes

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Our structure was designed with a “cold roof”, or ventilated roof assembly. By having continuous ventilation in our north and south soffits, with a ridge vent on the top of our roof, outdoor air can freely enter the soffits and exit out the roof’s ridge vent. The benefits of this set-up are explained in these comprehensive articles:

 

BSC – Roof Design

 

All About Attic Venting

 

FHB Roof Venting

 

Here is the product we’re going to use in the soffits:

 

Cor-A-Vent

 

In order to make this kind of roof assembly work, insulation baffles or insulation chutes are necessary, especially if the attic is going to have any kind of significant amount of insulation, in particular blown-in insulation that could potentially move around and block off the soffit ventilation from the attic, thereby short circuiting air flow from the soffits through the roof’s ridge vent.

When it was time to install the insulation baffles, I assumed I could just go to one of the big box stores and (thankfully for a change) just buy something off the shelf. It didn’t work out that way.

At Home Depot they had Durovent (a foam based insulation baffle) and an AccuVent baffle (black plastic). Both were a disappointment.

I didn’t buy the Durovent — even just seeing it on the shelf and handling it in the store, it looked cheap and unimpressive. It was hard to imagine it holding up under the pressure of any significant amount of blown-in insulation pressing against it.

 

 

The AccuVent product Home Depot carried only worked in a straight line (no curve to wrap over the back of the Zip sheathing at the top of the wall assembly), ideal for a cathedral ceiling application. After looking around online, I found this other AccuVent product:

 

 

Seeing the video made me think it would be an easy installation, but once I had the product on the job site and tried to install one, the realization hit that they would be a pain to properly air seal, and again, I had concerns about blown-in insulation pressing up against it for years.

 

AccuVent out of the box

AccuVent on the job site. It’s hard not to look at these foam/plastic baffles, regardless of brand, and not think: “flimsy”.

 

Here’s the specific product info:

 

AccuVent label close up

 

And here are the installation instructions:

 

AccuVent install label

 

When I realized the AccuVent wasn’t right for our project, it was a moment of, “Uh-oh, now what the hell do I do?”

I assumed there must be a sturdier plastic baffle, but I never found one. Instead, I came across this article:

 

Site Built Baffles

 

As usual, old reliable — GBA — had already addressed the issue.

It was nice to have a solution, but I also knew it would be time consuming and back breaking (also neck straining) — the only thing worse than working with sheet goods is working with sheet goods above your head on a ladder. Nevertheless, I would sleep better knowing it was panels of OSB rubbing up against 2 feet of blown-in cellulose insulation rather than sheets of flimsy plastic. Long term solutions do wonders for peace of mind.

 

first chute installed and sealed

First insulation chute installed.

 

I used small, cut pieces of 2×4 (six per OSB sheet) as a screwing base (visible in the photo below) to install each insulation chute  — screwing the blocks first to the roof trusses, then, after putting the OSB into place, screwing through the OSB and into the bottom of each 2×4.

 

close up looking down chute before sealing

The blocks were first screwed to the trusses, before each sheet of OSB was attached to the 2×4 blocks from below.

 

Then, after installing each sheet of OSB, I went around the perimeter sealing all the gaps. Here’s the product I used for that:

 

close up Quad Max product label

The OSI sealant I used to cover the gaps.

 

Here’s what the chutes looked like once they were installed on the south side of the house:

 

insulation chutes long view

 

And this is what the chutes looked like when completed at the top of the Zip sheathing:

 

sealed top of wall w: sealed insulation chute

 

There weren’t always sizable gaps where the OSB chute met the top of the Zip, but when there were, this was pretty typical:

 

unsealed warped chute before sealing w: small piece

 

Same area after adding a thin piece of OSB to help cover the gap, and then sealing the area with the OSI sealant:

 

sealed small piece at bottom of chute

 

Looking down a chute before sealing with the OSI:

 

close up looking down chute before sealing

Gaps visible at the edges before sealing them up with the OSI.

 

Same view after sealing up the gaps:

 

close up looking down sealed chute

 

I showed up on a rainy morning to continue installing the chutes, and this picture shows the dramatic before and after view of without chutes and with chutes installed and sealed:

 

blue glow before and after chutes

On the left: no chutes and light visible through the soffit. On the right: chutes installed and  completely sealed.

 

Here’s a long view of the chutes:

 

epic long view of insulation chutes

49 installed with one to go (far left corner).

 

 

insulation chutes in corner

Final chute installed and sealed.

 

 

insulation chutes from outside

View from outside showing the ends of some of the OSB chutes peeking over the edge of the soffit.

 

 

close up of OSB insulation chutes from outside

Closer view of the top of the Zip sheathing meeting the OSB chute.

 

 

Intello from attic w: insulation chutes in bg

In the attic with the insulation chutes in the background, after the Intello was installed on the ceiling below.

 

Once the chutes were installed, I was finally ready to put the Intello on the ceiling, which thankfully I didn’t have to install by myself.