Spray foam for interior walls with external siding and rigid foam
My house has existing vinyl siding with 1″ foam (not sure what kind yet) installed over the old clapboards and then the vinyl. Inside, there is no insulation in the 2×4 stud walls covered with crappy drywall. This is a coastal house in Zone 5 (Massachusetts).
The wind blows through all the exterior siding, mainly due to poor window installation. I will be replacing the windows and drywall, correctly flashing the windows. After that, my question is about the interior wall insulation. Can I just spray open or closed cell foam in between the studs and cover with drywall? My building inspector says anything is fine with him, no need to go to code (R21), he just wants anything better than nothing. I am hoping the spray foam will block any air leaks that blow through the exterior.
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