Smart vapor retarder (ie: MemBrain) installation details
I’m currently in the final estimation phase of my upcoming new build and we’re coming in a little tight – so every little bit needs to be justified.
I’m located near Ottawa, Ontario where unfortunately poly vapor barrier is still required in the builders and inspector’s eyes. Our walls will feature 1″ foil-faced polyiso on the outside and R-22 of rock wool on the inside. The exterior foam has very low water permeance and consequently I want to avoid trapping moisture – thus the Certainteed Membrain. I had our GC price it out with the insulation sub and it came back with an upcharge of nearly $2000. This is a 2800sf, 2-storey house with full basement. If my calculations are correct, we’re talking less than 6000sf of wall and ceiling area. Finding pricing on the Membrain is a little hard in my area, so based on US pricing (Menards) 800sf of Membrain is $110 as opposed to $42 for the regular 6mil poly. Since this doesn’t add up to the $2000 up charge… my question is: Is there a significant amount more detail work that is required when working with the smart vapor retarder?
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