Insulation question for new house build
I’m building a brick bungalow in zone 5, please help critique my insulation. The sheathing is 1” Polyiso (foil faced) wrapped in Typar building wrap. I realize the polyiso should be thicker, but I’m told it’s too late. The walls are up and the windows are purchased.
Attic – R50 loosefill cellulose
Main Floor – R22 CC spray foam in 2×6 wall with no VB, drywall and latex paint
– The other option is R10 CC spray foam with R14 Roxul and no VB.
Rim Joist – R12 CC spray foam and R14 Roxul (thermal barrier required)
– I understand it’s a double VB, and from what I read, the 2” CC spray foam has a permeability of 1 perm. My concern is whether it’s enough to dry, as the exterior rigid foam is not thick enough to keep the dew point out of the wood. I’m concerned about this design, but I’m not sure of a better solution.
Basement – 2” R12 continuous CC spray foam, 2×4 stud with R14 Roxul, no VB, drywall and latex paint
Under slab – R10 rigid insulation
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