Wall assembly (Zip R) for mixed humid
cnote75
| Posted in Energy Efficiency and Durability on
Hey Folks,
My architect has planned a 2×4 wall with Zip R 1″ foam sheathing. It will likely have batt or blown insulation. I see a ton of Zip sheathing around here, but I doubt much of it is insulated. Should this assembly hold up in my climate 4A (mixed-humid). I particularly concerned about vapor permanence and drying.
Thanks!
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Replies
C. Maglio,
Q. "Should this assembly hold up in my climate 4A (mixed-humid)?"
A. Yes. I haven't heard of any durability problems with Zip-R.
Q. "I particularly concerned about vapor permanence and drying."
A. Zip-R has a vapor permeance that is less than 1 perm, so don't expect your wall assembly to dry to the exterior. If you use this type of sheathing, your wall assembly should be designed to dry to the interior. (That means that you shouldn't install any interior polyethylene or vinyl wallpaper.)
Zip R has inner face foam. That foam layer protects the OSB from condensation damage IMO. I think it is a great product to use with dense pack insulation, glass or cellulose. Add a pressure treated bottom sill plate to the mix and I like. Add a double wall to the plan nice.