Hello and thanks to all for an amazing community of helpful folks. I am building a ranch style home over a 4ft Crawlspace in zone 6a. My question pertains to the Crawlspace wall detail. I have read all the quintessential GBA articles on encapsulation. My problem specifically is that I am planning to use reclaimed 2.5 in fiberglass faced industrial roofing polyiso. It seems to already have a bit of an odor to it. I was thinking it would be nice to place the insulation against the concrete wall then place the polyethylene over the top to seal any smell out. Will this cause moisture issues? What about a smart vapor retarder to seal the smells but allow vapor passage if need be? Planning to keep the polyiso off the Crawlspace floor so only moisture would come directly from concrete. Thanks for any and all advice. Matt