We just bought our first home. The basement is mostly finished, except for a side room that contains the furnace, washer, and dryer, and some storage space. We’d like to finish that room and put a small office at the end.
My general plan is to install XPS foam against the concrete, then frame a stud wall against the foam, and finally install drywall. The room is already pretty small, so I’m trying to minimize the width of the wall if at all possible. I could get R13 batts, which would meet code, but from what I have read I still need some sort of vapor barrier between the studs and the concrete.
First question: How thin could the foam be in order to provide the proper vapor barrier? Would 1/2″ be too thin?
Second question: The previous owner painted the concrete with some sort of waterproofing paint. Is that going to be problematic with my above plans? Wondering if I should try and remove it, or if it is fine as is.
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