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Passive House + Zero Net Energy + Permaculture Yard

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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!