Polyiso on the inside?
A question from a DIY prospective…. I can see a point of adding rigid foam insulation on the outside. But for a 2-story house, and a do-it-yourselfer, it is a bit of a scary project – you have to complete a lot of work in a short time, and get a lot of details just right.
Adding insulation on the inside, on the other hand, allows one to work at a more flexible pace. Even if it takes a year to do it room-by-room, you don’t expose your house to the elements. You don’t get a continuous thermal envelope, of course. The general idea is to remove drywall, fix whatever is wrong with fiberglass batts, add 2″ of polyiso, furring strips, and then drywall. Sort of like insulating a basement. Does it make any sense, or is it just inviting trouble?
I am in northern part of Zone 4. Current insulation is 4″ fiberglass batts with paper to the inside.
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