R45-50 thick walls, rigid on outside or closed cell spray foam on inside with cellulose?
I’m planning a super insulated, super tight house in upstate New York. I’ve seen lots of double wall details using 2-3″ of spray foam on the inside and 9-10″ of cellulose to fill the remainder. I have not seen any details using 2-3″ rigid insulation on the outside of the sheathing with 10″ of cellulose in the wall cavity. Would both types of walls perform similarly? Is there an advantage to one over the other?
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