thermal bridge free exterior

next up on skidmore passivhaus is installing the outsulation on the walls along with the rainscreen furring.

the plywood sheathing was first covered by a weather resistive barrier with metal head flashings at the windows and doors.

most walls get a layer of 3″ poly-iso, while the south wall will get 4″ to match the recessed pocket for the exterior shades.

2 screws (with plastic washer) per 4×8 sheet hold it in place until the furring strips are installed.

all seams and fasteners are taped.  the face of the insulation is treated as a second weather resistive barrier.

additional flashings at all doors and windows will be taped to the insulation as the wood trim is installed.

1/2″ x 2″ pt plywood furring strips run vertically to create the drainage plane.  they are held in place by just a few fasteners until the next layer is installed.

since we are using vertical siding, a second layer of furring runs horizontally.  we used pt 1×4 as a solid nailing base for the siding.

long fasteners secure the second layer of furring strips running horizontally through the foam to the studs.  the straightforward framing layout makes the studs much easier to locate.

keep in mind that long fasteners get expensive.  we settled on grabber #10 x 6″ square drive coated screws (from nw staple).

next up on the exterior is trimming windows and installing siding.

stop by again soon.

foundation foam

while there’s a lot of talk these days about building without foam, we decided early on to use continuous rigid board foam outsulation for this project.  to begin the foundation gets 4″ of expanded polystyrene.

these 8′ long pieces are held in place at the bottom by backfill and at the top by concrete spikes.  spray foam was first applied to the back of the pieces to fill gaps and help secure them.

the concrete spikes are recessed into the foam to minimize thermal bridging.  only 3 spikes were used per 8′ long piece.

step 1: use hole saw bit and pry out hunk of foam.

step 2: use hammer drill to drill hole in foundation.

step 3: prepare 6″ concrete spike and plastic washer.  (concrete spike from dealers supply / plastic washer from service partners supply)

step 4: hammer spike and washer to secure foam.

step 5: spray foam any gaps

step 6: reinstall foam plug using spray foam as adhesive

when the weather warms we will be applying a cementitious coating direct to the foam to provide the finished surface.  after final grading, only 6″ or so will be exposed to view.

waiting for guffman (or looking through windows – part 8)

when we began this process, we only had a few rules.  one of them was real wood high performance windows.

at the conception of this project, we were thinking about making a pretty good house.  Super insulated, airtight, with triple glazed windows and a heat recovery ventilator, but not necessarily passivhaus.  since we ruled out plastic or fiberglass, US built windows were at the top of the list.  once we decided to build to passivhaus, it quickly became clear that we had to look overseas.

our initial pricing was from optiwin, internorn, and pazen.  optiwin was very appealing aesthetically but super expensive.  internorn provided fantastic pricing, but there was no rep in the US meaning distant communications and pretty much zero support. pazen offers a slightly different product with a fiberglass exterior cladding and more minimal frame profiles, but they only offered a stainless steel clad door.  because we had lots of doors, the price jump was huge and they were way out of our budget.

about the same time, our local loewen rep started offering unilux.  we visited another local passivhaus project to see them installed, and we were impressed.  the pricing was strong, and we felt most comfortable having a rep locally, although they only had a limited understanding of passivhaus.  we thought we’d made up our mind, until we stumbled onto zola windows.  nearly identical to the german and austrian made passivhaus windows, zola windows are manufactured in poland and offered at a much more competitive price point.  we worked through all the options, input the data into PHPP, and scrutinized the sample window section that we got our hands on.  it seemed like a good balance between quality, aesthetics, and price point.  decision made.

one of the biggest challenges of using european windows is the long lead time (for our order the lead time was estimated at 12-16 weeks).  we worked hard to have our window order ready to go by the time we were breaking ground.  once we placed the order, the race was on to make sure the house was ready when the windows finally arrived.  18 WEEKS LATER they finally arrived. when we finally opened the container door to check them out, 2 of the biggest units had broken free from their braces and had fallen over at somepoint during shipping.  while nothing was catastrophic, there were issues both functional and aesthetic.

fast forward 6 weeks.  zola has been super responsive and we’re confident that in the end everything will be as good as new.  the windows and doors are installed and are beautiful.  the house is dry, the first blower door test went well (.44ach at 50pa), and we are steadily moving toward insulation and sheetrock.

here’s a quick look at some of the process. first, prepping the rough openings:

step 1 – use pink prosoco joint and seam filler at corners and joints of rough opening.

step 2 – use red prosoco fast flash to coat rough opening and extend approx. 6″ out onto sheathing.

to apply these prosoco products, simply lay down a bead from a caulking gun and spread with a cheap plastic spreader.  the result is a waterproof, airtight, and vapor permeable flashing without the usual complications of peel and stick flashings.  of course no through wall metal flashings on a passivhaus.

next, windows arrive and are unloaded.

not what you want to see when you open the door of the container.  i think they forgot to do the ACTUAL bracing at the factory.

some of these units are HEAVY!  thank to Doug Marshak and his Awesome Framing Crew for doing the very heavy lifting.

small tilt/turn unit for the kitchen.

Doug and Jesus installing the small window in the 2 story living room.

the big units waiting to be installed.

after a few nervous hours, the biggest unit finally goes in.  thanks to Graeme Thomson for the smart hoisting method.

the large fixed unit installed above the lift/slide door.

front door with translucent glass and large window to the street.

breezeway with tilt/turn terrace door and fixed sidelite.

studio with tilt/turn door and fixed sidelite.

check back soon for more as we try to catch up with construction: HRV rough-in, steel stair installation, flashing the windows, installing the exterior insulation, and rainscreen furring.