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net zero | passive house, western maryland: coming to a close

We are thrilled at the success and completion of our first Foam-Free, (near) Net Zero, Passive House in Western Maryland.  The home is currently in the final stages of testing and certification and interior finishing. It has been an educational process with material usage, system selection and install, air sealing and insulation, window install and team collaboration.

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The views and placement of the house are extraordinary and achieve the homeowner’s goal of a comfortable, accessible, high performance home designed to view the meadow, marsh and forest.

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For more photos of the final walk-thru, visit the project page.

net zero | passive house, maryland: mento + furring

Upon hanging the TJI insulation cavity, the vapor open Weather Resistant Barrier (WRB) was installed and all seams were taped.  Given the pressure of the cellulose that will be blown-in behind this WRB, we decided to use Solitex Mento 1000 and taped with our favorite Tescon Vana tape.

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The next layer is the ventilation cavity / rainscreen / furring strips.  We decided on horizontal with vertical furring strips to keep the cellulose bulge in check and maintain an acceptable ventilation cavity as well as provide a more substantial nailing surface for our engineered wood siding.

net zero | passive house, maryland: hanging the TJI insulation cavity

We have built our structural 2×6 wall, installed and taped the plywood air barrier, and have created all of the window boxes.  It is now time to attach the 11 7/8″ vertical TJIs to our wall.  This TJI cavity will be filled with cellulose and serve as our main insulation layer in our Climate Zone 5 project location.  The TJIs are non-bearing and their vertical installation is addressed by Weyerhaeuser TrusJoist TB-821-2014 (comes up on a google search).

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Per the advisement of our structural engineer, in the areas where the TJI is not resting on the concrete foundation wall (with a bit of mineral wool sandwiched between), but is instead ‘floating’ we used a light 40 series joist hanger at the base of each TJI.  He also called for blocking top, bottom and mid-height.

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net zero | passive house, maryland : window install mock-up

Michael Hindle, CPHC, and I headed out to Western Maryland to review the window box and TJI insulating cavity mock-up.  It was cold and snowy.  Really cold.  I think I was the only one that noticed. The Gosnell crew is amazing, and, apparently impervious to freezing temperatures.

I said it was freezing, right? FYI, because of the freezing temperatures we chose to use tape for our water-tight detailing rather than a liquid applied product.  Once again, the Tescon Vana tape performed extremely well.  That stuff would stick snowflakes together.

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As shown in the photos above, every corner of the box is being taped as well as every edge of the window (allowing bottom free draining).  Our 11 7/8″ TJI wall is resting on the 4″ block ledge with a spacer of mineral wool sandwiched between the plywood base plate and the block.  The window box is a 5/8″ plywood box with a horizontal TJI top and bottom.

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Teamwork, Teamwork, Teamwork.  It is really a pleasure to watch these guys take pride in their work and listen to and learn new ways of building.  Peaceful implementation by the contractor is such a key factor to making these super-tight and efficient envelopes successful. Teamwork is always LESSON ONE.

 

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8333 main street, 2nd floor · ellicott city, md 21043
410.313.8310 baltimore
washington