So working on a 9' ceiling exterior wall that is built of 3" x12" 12' "logs" framing wood, originally had planned to laminate XPS to the inside wall, furring then GWB, when we found out the flame retarder in XPS &EPS are banned in some countries and soon here.
So know what can we use to insulate (can't use spray foam either) on the inside walls where we only want to take up max 1.5" of space? Tintest maybe?
Confusing question. If you have 3 X 12 framing members, you should have plenty of room to put in whatever you want. I would recommend Roxul or equivalent rock wool insulation. It is fireproof and does not support mold. If you only have 1.5 inches, I think they make a fairly rigid exterior product for foundations that is R5, about the best you will get if you can't use XPS. You can actually fasten strapping through it and it doesn't compress.
More details may provide better solutions from other guys here.
Good luck with it.
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