How One Vancouver Builder Is Blowing The Doors Off Mid-Construction Air Tightness Testing
How did Sandro, from Abstract Homes beat the building code standards from the very beginning? Frankly, it was a bit of an accident. He did this while working on his current project on W15th Avenue in Vancouver.
Sandro’s initial thought, (which is the way he thinks about all his projects) was to build the home more energy efficient in general. He also wanted to make the home structurally stronger – which would make it above and beyond what the structural engineers require – so decided to use an advanced framing method using 5/8” T&G plywood as exterior sheeting, blocking all the joints. Not only did it make the structure stronger, he discovered the added benefit to doing this was it plugged up almost all of the holes you would get with regular plywood. Typically, a builder would use 1/2” plywood on the outside, leaving a half inch between the boards (required by the building code) then plug the holes with caulking to eradicate airgaps in the walls.
He also thought it would be an interesting idea to centre 4” T&G plywood between the upper and lower floors when joining them, which is a framing method that overlaps the boxer joists, leaving no airgaps in the walls at all. Centering the one sheet of plywood between the upper floor and the lower floor made the home, not only structurally superior, but left no place for the air to come in, blocking all of those holes that a builder would normally have to go back and caulk and fill.
Then came time for the blower door test. Also called the “pre-drywall blower door air tightness test” the blower door test is done when all of the windows, doors and insulation have been installed. This test is very important, as once the drywall is installed, problem areas are very hard to fix.
What happened? They ran the blower door test with NO vapour barrier or insulation - and were amazed when achieving a 2.8 air change with ONLY the exterior sheeting on the walls. This result meant Sandro had already achieved what is normally the EnerGuide rated standard for a finished home under the Vancouver building code, while still at mid-construction/pre-insulation.
Even more astonishing - was after the insulation was added to the home, a pre drywall test was run and again he had an amazing result. The test came back at a 1.8 air leakage result (Air Changes per Hour) which put the home at a higher standard than what was required to become an ENERGYSTAR* home for new homes - before even the drywall was installed. And to note - achieved with no caulking, which also makes the home a more natural, environmentally friendly home.
Watch the video with Sandro speaking with Emma Conway from E3Eco Group as they go through the steps and explain what a blower door test is and how the numbers came out on this particular home when they ran the testing.
Understanding your home air leakage results:
Average new construction Final Test Standard – 5
ACHVancouver Building Bylaw Final Test Standard – 3
ACH ENERGY STAR* for New Homes Final Test Standard – 2.5
ACH R-2000 – 1.5 ACH Passive Home – 0.6
ACH. For more information on the EnerGuide Rating for New Homes, click here.
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