8:26 pm - November 15, 2017 - Eric Whetzel

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.”

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.

Another view of the 2-layers, mostly installed:

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:

https://youtu.be/hz5IgqznNhU

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 during the pour.*

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.

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:

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:

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.*

long view of brace for pour — *The guys starting at the back of the basement.*

back corner of basement pour #2 — *One corner complete.*

troweling at stairwell — *Enrique completing the trowel finish.*

cement truck kissing corner of garage — *Side of the garage kissed by the cement truck.*

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 pink 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.

12:47 pm - September 19, 2017 - Eric Whetzel

Solar on the Roof

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

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

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

The System

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

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

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

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

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

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

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

conduit for solar in the attic after gasket — *3/4″ conduit sealed for a second time on the attic side of the Intello.*

solar mounting system being installed — *The guys setting up the racking system for the panels.*

close up solar base — *Close-up of the base that’s holding the solar panels.*

Rethink guys on the roof — *Anthony, Dan, and Cherif completing the install on the roof of the house.*

close up of solar panels being installed — *The low profile racking system has a very sleek look.*

Marking another big leap in the progress of the build:

solar panels on roof — *The view of our 11 solar panels from our neighbor’s driveway.*

solar panels installed on the roof.jpg — *Another view of the solar panels installed on the roof.*

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

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

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

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

The Cost

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

$12,519.50 Initial Investment

$(-3,755.85) Federal Tax Credit (ITC) 30%

$8,763.65 Net Cost of First Year

$(-3,816.00) Solar Renewable Energy Credits (SREC’s)

$4,947.65 Net Cost After All Incentives

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

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

Category: Net Zero Tags: chicago passive house, diy passive house, green building, greenbuilt home, Illinois Passive House, midwest passive house, Net Zero, passive house blog

3:02 pm - August 16, 2017 - Eric Whetzel

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 Building 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 picturing 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 lightweight. 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).

We started with these staples:

But we ended up going with these instead:

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).

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 underneath a roof truss, we were able to keep the 2×6’s fairly straight, even when an individual 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:

475 Intello w: furring strips on ceiling

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:

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.*

Category: Passive House Tags: chicago passive house, diy passive house, green building, Illinois Passive House, midwest passive house, passive house blog, passive house design

12:32 am - July 16, 2017 - Eric Whetzel

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:

And here are the installation instructions:

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, 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:

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:

Looking down a chute before sealing with the OSI:

Same view after sealing up the gaps:

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.*

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.

[December, 2020 Update: If you’re trying to avoid the time and materials associated with installing site-built plywood chutes, a newer (at least to me) product like Smart Baffles is probably worth considering:

https://dciproducts.com/smartbaffle/

Although, as with any new product, it’s worth the time and effort to do a mock up, in this case with a roof assembly (much like the one shown in their video), along with a partial wall assembly, in order to see how the product works (evaluate the durability of the product, ease of installation, final fit, etc.), especially where (and how) the baffle will meet up with the top of the outside walls. With a mock up, you can avoid (or work through) any issues with the product before you’re on the job site actually installing them (when time and money really matters).]

Category: Passive House Tags: chicago passive house, green building, Illinois Passive House, midwest passive house, passive house blog, passive house roof, site built baffles

2:57 pm - July 4, 2017 - Eric Whetzel

Roof Details (Air Sealing #3)

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Top of Wall and Roof Connection

Once the wall assembly details were figured out, and our ceiling set-up detailed, the transition between the two became the next challenge. In other words, how to carry the air barrier over the top of our exterior walls.

I found this helpful article by Chris Corson from The Journal of Light Construction:

An Affordable-Passive-House (pdf)

Using a waterproof peel-and-stick membrane to wrap over the top of the wall (going from exterior sheathing — in our case 7/16″ Zip sheathing — to interior side of the top plates) seemed like the easiest way to maintain a continuous air barrier at the wall-to-roof junction. The membrane would also have a nice air sealing gasket effect after the trusses were set in place.

I also found this excellent Hammer and Hand video on YouTube (one of their many helpful videos):

Wall-to-Roof Air Barrier

Also, by being able to carry the Zip sheathing up above the top plate of the wall, hugging the bottom of the trusses, meant our 4″ of Roxul Comfortboard 80 over the Zip sheathing would rise above the top of our walls, so that thermally we would be protected going from the exterior walls to the attic, which will be filled with 24″ of blown-in cellulose — making our thermal envelope continuous for the whole house: under the basement slab – exterior of foundation – exterior walls – attic (except for one small gap at the footing-slab-foundation wall connection, which I talk about in a separate post: Foundation Details).

A high R-value wall meets up with a high R-value attic, with no thermal bridging, making our thermal layers continuous. When this is combined with an equally air-tight structure, conditioned air cannot easily escape — resulting in a significantly lower energy demand for heating and cooling (and therefore lower utility bills), and added comfort for the occupants.

Here’s a nice illustration from Fine Homebuilding magazine showing a similar set-up:

I tried using rolls of conventional peel-and-stick window flashing membrane, purchased from Home Depot and Mendards, but they performed poorly, even in unseasonably warm temperatures for February in Chicago.

I then switched to Grace Ice and Water Shield, normally used as a roofing underlayment along the first 3-6′ of roof edge.

grace-ice-water-shield — *Purchased this box at Home Depot.*

Since it came on a long roll about 4′ wide, my wife and I cut it down to a series of strips that could more easily be applied to the wall-top plate connection.

While the sun was out, the Grace membrane worked fairly well, especially when pressure was applied with a J-Roller.

grace-vycor-in-the-sun-ii — *Grace Ice and Water Shield applied to the top of our wall — covering the Zip sheathing/top plate connection.*

Unfortunately, the sun and warmer temperatures didn’t stick around long enough for me to finish.

sealing top of wall w: Grace Vycor in sun — *Using a J-Roller to get the Grace Ice and Water Shield to stick better.*

grace-vycor-in-the-sun — *This Simpsons sky didn’t last long. In a matter of hours it was back to rainy, gray, and cold — typical Chicago winter weather for February.*

When the weather went gray and cold again, we started to use a heat gun to warm up the Grace membrane, which had turned stiff and nearly useless in the cold.

wagner-heat-gun — *Wagner heat gun for warming up the Grace membrane.*

After wasting a lot of time and effort trying to pre-heat the Grace membrane before installing it, I finally relented and switched to the much more expensive (but also much more effective) Extoseal Encors tape from Pro Clima. Where the Grace membrane lost virtually all of its stickiness, the Extoseal Encors stuck easily and consistently, with the J-Roller just helping it to lay flatter and more securely.

extoseal-encors-as-gasket — *Pro Clima’s Extoseal Encors available from **475 HPBS**.*

It was a case of trying to be penny wise but ending up pound foolish. Looking back, I would gladly pay an extra $300 in materials to have those hours of frustration back (including the time it took to run to the store and buy the heat gun, which turned out to be ineffective anyway).

installing Extoseal Encors on top of wall cloudy — *Finishing up the top of the wall.*

After finishing sealing the Zip sheathing-top plate connection on all the outside perimeter walls over the weekend, it was time for the trusses to be installed.

Trusses

Zach asked me to stand by the front door rough opening and give the crane operator hand signals. It was a fun way to watch the roof take shape.

first-truss-swinging-into-place — *First truss swinging into place.*

trusses-going-in-from-inside — *Sammy, Zach, and Billy (out of view to the right), landing and setting the trusses.*

Once the trusses neared the front door, Zach could signal the crane operator himself, so I was able to get some shots from just outside the construction fence.

starting-garage-trusses — *Sammy, Zach, and Billy landing trusses on the garage.*

long-view-of-crane-and-house-east-side — *Setting the trusses on the garage. The basic silhouette of the house starts to come to life.*

Once the trusses were on, and the guys had a chance to install the final top row of Zip sheathing (up to the bottom of the trusses on the exterior side of the wall), I could move inside to seal all the connections from the interior.

Top of Wall (Interior)

Because of the cold, the Grace membrane was beginning to lift at the edges in certain spots, so just to make sure it had a nice long-term seal, I went around the perimeter of the house and used a layer of Tescon Vana (3″ wide) tape to seal the edge of the Grace membrane.

sealed top plate from interior — *Trusses sitting on Grace and Extoseal Encors (other sections of top plate), with the final, top row of Zip sheathing sealed to the trusses with HF Sealant.*

The picture below shows all the connections involved: top of Zip sheathing meeting the roof trusses and the top plate of the outside wall:

sealed top of wall from inside — *HF Sealant helps to air seal the Zip-truss and Zip-Grace/Extoseal Encors connections.*

view of top row of Zip sheathing 1 — *Looking up at the top row of Zip sheathing attached to the outside edge of the raised heel trusses.*

Shingles

We had to wait for shingles for quite some time. First we had to fire our GC’s, and then I had to find a roofer and a plumber (to make penetrations through the roof before the shingles went on). But before the plumber could even start, I had to get the Intello installed on the ceiling. And even before that, I had to figure out the insulation baffles, which I’ll talk about in a separate post.

It took awhile to find a roofer since they would have to make three separate trips for a relatively small job. The first trip was just to set down the Grace Ice and Water Shield at the edges of the roof, along with a synthetic roof underlayment (the consensus was that typical roofing felt wouldn’t hold up to long term exposure). As it turned out, it took weeks before the plumbers made their penetrations through the roof sheathing (literally the day the roofers showed up — a long, horrible story in and of itself that I’ll save for later).

synthetic underlayment at roof peak — *Synthetic underlayment covering the ridge line until the shingles and a ridge vent can be installed.*

The second trip out was to install the shingles on the roof of the house, while the third trip to install shingles on the garage roof could only happen after the Roxul on the exterior of our Zip sheathing was installed (in order to make a proper sealed connection between the wall of the house and the garage roof).

There weren’t many roofers willing to work with our unique Passive House sequencing, but our roofer was kind enough to take it on.

Grace ice and water shield rolling up after wind — *Grace Ice and Water Shield rolling up on itself after the wind got ahold of it.*

Unfortunately, the day after the guys installed the Grace membrane and the synthetic underlayment, we had a cold, blustery day. Once the wind grabbed the Grace membrane, the membrane rolled up on itself, turning it into a real mess.

Because of our recent past bad experiences with general contractors, I just assumed I was on my own, so I spent a couple of hours putting down new layers of the Grace membrane. When Peterson roofing found out, they were shocked I did it myself, and assured me I could’ve called them and they would’ve come back out. We were so used to people not following through, that low expectations meant it didn’t even occur to me to call them.

We initially were going to use Certainteed’s Landmark TL shingle, which mimics a cedar shake shingle profile, but Armando from Midwest Roofing Supply in Schaumburg, Illinois was kind enough to take the time to walk me through the options available, and explained that because our roofline isn’t steep, only the neighbors from their second story windows would get to appreciate the effect. He recommended we save some money, while not giving up on quality or durability, and go with the Landmark Pro product.

shingles being installed w: vents — *Shingles going down on the roof of the house.*

The shingles went on quickly since we have a relatively small and simple roof. In addition to the aesthetic leap the shingles made on the appearance of the structure, it also meant I didn’t have to go around cleaning up the subfloor every time it rained.

Although the synthetic underlayment worked pretty well at keeping the rain out, if there was significant wind combined with rain, the water easily found its way under the underlayment where it could then drip and fall on the subflooring below — pretty depressing showing up to the job site after a hard rain knowing I was going to spend the first hour just cleaning up and looking for leaks.

roofers shingling south side — *Seeing this felt like a tremendous amount of progress was being made. It also meant an end to our roof leaks on the interior.*

shingle installation progressing — *Shingles going on quickly. Only two penetrations through the roof — main waste stack and radon.*

After they cut the opening for the ridge vent, but before it was installed, I managed to get this shot from inside:

attic just before ridge vent installed — *Attic as cathedral.*

Category: Passive House Tags: air sealing a passive house, chicago passive house, diy passive house, green building, Illinois Passive House, midwest passive house, passive house blog, passive house design

12:55 pm - May 16, 2017 - Eric Whetzel

The Passive House Nightmare: Part 3

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This can’t be happening again…

It is February of 2017 as I write this.

This project began for us back in the summer of 2014 — nearly three years ago — when we first sat down with Brandon Weiss in what was then his new office in Geneva, Illinois. As detailed here…

The Passive House Nightmare

…things didn’t go well for us with Brandon and his company, Evolutionary Home Builders.

After we decided to move forward and try to complete what we started, the question became:

Who do we hire as our next builder?

After our interactions with Mark Miller and Katrin Klingenberg, detailed here:

The Passive House Nightmare: Part 2

PHIUS (Passive House Institute US) did not seem like a resource we could utilize — the Passive House world is small, smaller still when you reduce it to a single geographical area like Chicago and its surrounding suburbs. And the thought of interviewing conventional builders, and trying to convince one to take on the detail required in a Passive House level build, seemed overwhelming.

As a result, we decided to go with two guys close to home who have conventional building experience.

The logic underlying the relationship was that they would GC the build, taking care of all the conventional building details, while I took care of all the Passive House details.

Unfortunately, this proved fruitless.

Events revealed they didn’t have the requisite skill set necessary to complete the job, and we have subsequently taken over the project ourselves. It’s taken weeks to get things back on track, hence the delay in posting anything new regarding the progress of the build.

When the build is complete, I’ll return to this matter, offering more details that will hopefully help other consumers who want to build a new house avoid our unfortunate experience.

The really sad thing is there are quality people who make a living as general contractors, but unfortunately it remains a minefield out there for consumers without meaningful connections. If you don’t already know the answer to the question ‘Who should build our new house?’ before you start the process, then it’s truly a case of caveat emptor. And if things should go poorly, you will feel like you’re on a very lonely island.

Details to follow…

Category: PHIUS Tags: Brandon Weiss, chicago passive house, Eric Barton, Evolutionary Home Builders, Illinois Passive House, Katrin Klingenberg, mark miller chicago architect, passive house blog, PHIUS review

4:32 pm - January 25, 2017 - Eric Whetzel

Framing (Air Sealing #2)

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Mudsills

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

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

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

bill-and-phil-setting-up-chalk-lines-for-mudsill — *Billy and Phil setting up chalk lines for the mudsills.*

nils-running-bead-of-sealant-before-mudsill-goes-down — *Nils applying a thick, continuous bead of **Contega HF sealant**, including around the bolts, before the 2×6 pressure treated sill plate gets installed with a BG65 gasket underneath.*

ct-gasket-close-up-on-srap-board — *BG65 gasket from **Conservation Technology** stapled to the bottom of a scrap piece of sill plate.*

ct-gasket — *BG65 gasket rolled up in the box it shipped in.*

*Sammy and Billy stapling the BG65 gasket to the sill plates before installation.*

mudsill-squeeze-out — *Mudsill installed with some squeeze out of the sealant.*

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

selfie-by-window-buck — *In theory, she’s helping me.*

mudsill-with-gasket-and-sealant-garage-from-inside-basement — *Mudsill after installation: sealant covering sill plate – BG65 gasket – concrete connection, with seams filled.*

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

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

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

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

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

This is what it looks like:

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

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

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

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

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

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

backer-rod-by-header — *Example: Piece of backer rod being inserted into gap between header and 2×6.*

garage-mudsill-w-gasket-and-sealant-corner — It’s not visible, but the wood-concrete connection at the side wall has a piece of backer rod embedded between the two materials, making it easier for the sealant to bridge the gap over the long term.

Air Sealing: Rim Joist – Floor Joist – Mudsill Connections

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

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

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

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

The same areas after applying the sealant:

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

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

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

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

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

Knee Walls Installed

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

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

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

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

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

20170105_121618 — *Knee wall being covered in Zip sheathing.*

zip-on-framing-covering-tescon-vana-w-roxul-below — *Close-up of knee wall with Zip sheathing and sealed seams.*

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

*Taped bottom edge of Zip sheathing over face of mudsill.*

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

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

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

Subflooring

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

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

liquid-nails — The product takes much longer to dry when it’s cold and wet outside — at least 2-3 days in our experience (sometimes even longer). It’s nice to see more “green” products showing up in the big box stores, rather than having to always special order them.

view-of-water-tower-from-kitchen-doorway — *Standing by what will be the kitchen door. The subflooring was installed with nails and Liquid Nails subfloor adhesive.*

rim-joists-at-outside-corner-sealed-up — *Corner of our slowly growing wall assembly. The connection between the subflooring and the top of the rim joists was eventually sealed with the Contega HF sealant.*

Basement slowly being covered by subflooring:

Walls Go Up

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

subfloor-done-blank-canvas — *Our blank canvas.*

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

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

men-at-work — *Men at work: Zach, Phil, and Sammy laying out the walls.*

zip-going-on-the-walls-w-bead-of-adhesive — *Zach and Phil installing the Zip sheathing over the framing.*

zip-sheathing-w-phil-putting-on-continuous-bead-of-adhesive — *Phil laying down a consistent and continuous bead of construction adhesive (trying to avoid a bead that runs back and forth between fat and thin), before the Zip sheathing is installed.*

wall-being-prepped-w-tescon-vana-on-seams — *We were fighting the rain, ice, and mud, but I was able to get the Tescon Vana tape over some of the seams in the Zip sheathing before the walls went up.*

sealant-on-nail-holes-in-zip — *Sammy and Billy help me apply the Contega HF sealant to each nail hole, and then make it lie flat with a swipe of the spatula, so the Tescon Vana tape that will be applied later will also lie flat.*

zip-sheathing-prepped-w-tescon-vana-and-sealant-on-nail-holes — *Section of wall nailed, taped, and nail holes caulked — ready to be raised up.*

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

billy-zach-sammy-south-wall — *First section of wall going up: Billy, Zach, and Sammy doing the heavy lifting.*

phil-zach-plumb-sammy — *Zach establishes plumb, while Phil readies to make the wall secure.*

all-together-south-wall — *The guys continue with the south walls.*

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

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

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

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

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

wall-at-corner-w-b75-gasket-underneath — *Wall is up.*

wall-at-corner-w-b75-gasket-view-down-ext-side-of-wall — *Same corner as above, but now looking down the exterior side of the wall.*

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

billy-and-sammy-insulated-headers — *Billy and Sammy putting the insulated headers together.*

4th-wall-missing-from-backyard — *End of the day. The fourth wall awaits.*

east-facade-w-zip-sheathing — *First look at what will become our front facade.*

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

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

leaning-over-top-of-zip-sheathing — *Leaning over the top of the wall to install the decking screws.*

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

sealant-with-water-tower — *Nice view as I apply the sealant.*

blue-chicken-pox — *My wife giving our Zip sheathing blue chicken pox with the Tescon Vana tape in order to seal all the nail holes.*

tescon-vana-embedded-in-ice-on-sill — It’s difficult to see, but this tape is embedded inside a sheet of ice. It rained overnight, before turning to ice. We’re asking a lot of these tapes and sealants. This piece of tape looks like fingertips holding on for dear life.

beast-looking-at-view-from-br-for-1st-time-close-up — *The Beast gets a first glimpse of the view from her bedroom window.*

pro-clima-pressfix — *I was wondering why I would ever need more than one of these. Now I know — bent, scratched, and cracked, the Pressfix from 475 HPBS did its job well.*

Category: Structure of House Tags: chicago passive house, diy passive house, greenbuilt home, Illinois Passive House, midwest passive house, passive house blog, passive house design, passive house wall assembly, zero energy ready home

4:08 pm - January 2, 2017 - Eric Whetzel

Foundation Details (Air Sealing #1)

14

Footings

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

Here’s a detail from the construction drawings:

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

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

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

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

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

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

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

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

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

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

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

Foundation Walls with Roxul Comfortboard 80

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Attaching Roxul Comfortboard 80 to Exterior of Foundation Walls

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

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

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

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

rodenhouse-fastener-box-w-label — *The box the fasteners came in.*

in-the-trenches-w-roxul — *In the trenches, as the second layer of Roxul gets attached with the Rodenhouse fasteners.*

long-narrow-piece-of-roxul-w-3-fasteners — *Long, narrow piece of Roxul with 3 Rodenhouse fasteners.*

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

Thermal Bridging in the Foundation

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

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

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

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

Here are some photos showing these connections:

foundation-north-corner-garagehouse-connection — *Garage foundation meeting up with corner of house foundation (north side of house).*

foundation-garage-house-connection-north-corner — *Close-up of this garage-house foundation connection, from inside the garage.*

foundation-front-porch-garage-to-house-porch-to-house-connections — *Front porch. Thermal bridge from garage to house is off to the far right.*

foundation-garage-house-connection-inside-corner-of-garage-inside-corner-of-front-porch — *Inside corner of garage where garage-front porch-house connect.*

foundation-front-porch-to-house-connection-outside-corner-of-porch — *Outside corner of front porch. Technically, another thermal bridge from porch to house foundation.*

foundation-side-porch — *Wing wall for side porch stoop. Yet another thermal bridge to the house foundation.*

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

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

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

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

Flat Rock Passive House: A Tale of Two Foundations

side-porch-getting-wrapped-in-roxul — **AFTER**: Wrapped in snuggly blanket of Roxul. The wing wall was eventually entirely covered except for the tops.

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

south-inside-corner-of-garage-w-roxul — *Corner of garage foundation meeting up with house foundation (standing inside garage).*

south-view-of-garage-house-foundation-connection-w-roxul — *Same corner, from outside, looking at house foundation to the right.*

inside-garage-garagehouse-connection-w-roxul — *Garage-front porch-house connection (from inside garage).*

front-porch-w-roxul — *Outside corner of front porch meeting up with house foundation.*

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

Basement Windows and Roxul

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

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

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

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

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

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

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

A few suggestions for using the HF Sealant:

I’ve found that completely snipping off the metal clip on the end of the sausage (as opposed to just cutting a couple of small slits around it) prevents it from getting jammed in the front end of the gun.
If I have a half-finished sausage of HF at the end of the day, I put it in a tightly wrapped plastic bag overnight (see photo below), which allows me to use it within a day or two without any problems.
Use a tiny spatula (see photo below) to tool the HF into place rather than your finger, as you normally would with a caulk — it’s just too sticky.
Because the HF is so sticky, I wear Nitrile gloves, so when it starts to get everywhere — and it will get everywhere if you let it — I just simply change to a new pair.
For clean up, the Citrus Solvent we’ve been using with the tung oil works great.

newborn-sausage-gun — *The Newborn brand of sausage gun we’re using for the HF sealant. Found it on Amazon. A really well-made tool.*

ateco-spatula — Found this on Amazon. I thought it was construction grade, but it’s made for kitchen use. It’s durable, and I like the thin blade since it offers more “feel” than a thicker blade, making it easier to tool the HF into place without displacing too much of it in the process.

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

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

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

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

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

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

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

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

This video was my Bible for installing the Extoseal Encors:

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

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

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

basement-window-buck-before-roxul — *Basement window buck sealed and taped on the exterior side before being covered in Roxul.*

close-up-basement-wdw-buck-covered-by-roxul — *Basement window buck surrounded by two layers of Roxul.*

basement-window-buck-and-roxul-meet-up — *Close-up of outside edge of basement window buck and Roxul connection.*

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

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

foundation-concrete-jewelry — *Concrete jewelry.*

queen-of-dirt-mountain — *Queen of Dirt Mountain.*

Category: Structure of House Tags: chicago passive house, diy passive house, Illinois Passive House, midwest passive house, passive house blog, passive house design, passive house foundation, passive house insulation

4:30 pm - September 11, 2016 - Eric Whetzel

Wall Assembly

2

Or: Dude, what’s in your walls?

When choosing what to put in our walls, we knew we wanted to try and balance high R-values (well above the current building code) with a limited environmental impact.

Here are three articles that address the issue:

Best Wall Choices

Without Foam

Twinkies

After evaluating various materials, including sheep wool,

goodshepherdwool.com

blackmountaininsulationusa.com

we decided to use many of the following elements employed by Hammer & Hand:

madrona-wall-assembly-914x1024-e1459377577722 — *Hammer & Hand wall assembly for their ‘Madrona House’.*

In terms of materials, there are any number of options for putting a wall assembly together. For instance, we really wanted to use the sheep wool, but cost and worries (unfounded or not) about availability, led us eventually to Roxul (the Hammer & Hand videos below proved especially helpful in this regard).

After seeing the wall assemblies Hammer & Hand has been using, and how they’ve evolved over time, we felt the Madrona House set-up represented a good balance between cost-environmental impact-availability-ease of installation. We will also be following their lead by using the Prosoco R-Guard series of products to help with air-sealing our building envelope.

Nevertheless, we did make a couple of changes to the Madrona House set-up. For example, we’re using 4″ of Roxul Comfortboard 80 on the exterior side of the Zip sheathing (based on our colder climate zone), and we will be using Roxul R23 batts in the stud bays, along with the Intello vapor retarder, stapled and taped to cover the stud bays. Otherwise, we will be sticking pretty close to the Hammer & Hand Madrona House wall assembly.

So from drywall to exterior siding (interior – exterior), this will be our wall assembly:

5/8″ Drywall
Intello Plus vapor retarder (475 High Performance Building Supply)
Roxul R23 Batts in 2×6 stud bays (24″ o.c.) (roxul.com)
Zip board (for structural sheathing and WRB; seams covered w/ Joint and Seam Filler)
4″ of Roxul Comfortboard 80 (two layers: 2″ + 2″)
2-Layers of 1×4 furring strips (aka battens or strapping) as a nailing base for the cedar siding
1×6 T&G Cedar (charred and oiled with a few boards left natural as an accent — most of it oriented vertically, hence the need for a second layer of furring strips).

wall-assembly-color-coded — *A crude rendering of our wall assembly using my daughter’s colored pencils.*

A collection of helpful videos explaining the various elements we’re going to use, and why they’re effective:

https://youtu.be/dgWOXdV6Srg

https://youtu.be/DCHppDNyfKw

Without the information available from sources like Building Science Corporation (they have a lot of interesting research documents) and design-builders like Hammer & Hand (not to mention Green Building Advisor and similar sites and forums that allow consumers to Q&A with expert builders and designers in “green” architecture), trying to build structures to such exacting standards (e.g. Passive House – Pretty Good House – Net Zero) would be exceedingly difficult, if not impossible, for those without previous, direct experience in this type of building program. I can’t express how thankful I am that so many individuals and businesses like these are willing to share their years of experience and knowledge with newbies like myself.

Here are the Hammer & Hand videos that initially sparked my interest in using Roxul rather than foam:

Instead of using tape for exterior seams, we are going to use the R-Guard series of products from Prosoco:

For various interior seams and connections we anticipate using the Tescon Vana tape, or an appropriate gunned sealant.

Helpful Links

GBA (Green Building Advisor): Building Green (Starter Q&A)

GBA: Article on minimum thickness of exterior foam by climate zone

GBA Question: Foam vs. Roxul

GBA: 10 Rules of Roof Design

GBA: “Greenest”

GBA: Passive House Design (5-part video series) Requires membership after Part I, but well worth it.

BSC (Building Science Corporation): Perfect Wall (pdf)

BSC: Hygrothermal Analysis of Exterior Rockwool Insulation (pdf)

BSC: Moisture Management for High R-Value Walls (pdf)

BSC: Cladding Attachment Over Thick Exterior Insulating Sheathing (pdf)

GBA: Mineral Wool Over Exterior Sheathing

Passivhaus Trust (UK): how-to-build-a-passivhaus-rules-of-thumb (pdf)

Also worth considering:

GBA: The Pretty Good House

GBA: Passive House Certification: Looking Under the Hood

Category: Passive House Tags: chicago passive house, diy passive house, green building, Illinois Passive House, midwest passive house, passive house blog, passive house design, passive house insulation

5:14 pm - June 13, 2016 - Eric Whetzel

“How did I get here?…”

0

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Category: Passive House Tags: green building, greenbuilt home, Illinois Passive House, midwest passive house, passive house blog, Pretty Good House