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Crawl space insulation

coalminer

New member
Joined
Jun 13, 2025
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2
I had to remove the subfloor above a crawl space. I removed the pink insulation and noticed some holes in the belly wrap. What is my best option to reestablish a vapour barrier? Can I install a closed cell Styrofoam and seal it from the top and put pink insulation on top?
 
Great project! Sealing the floor assembly over a crawl space drastically improves performance. Avoid placing rigid foam under fiberglass insulation. That traps condensation in the fiberglass between 2 vapor barriers, the foam below and the subfloor above, which can cause moisture problems. Instead, cut rigid foam to fit between joists, press it against the subfloor and seal the edges with canned spray foam. Is your crawl space vented or sealed and conditioned?
 
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