Crawlspace Insulation; getting conflicting information
I recently bought a 1974 single story ranch house in the northern front range of Colorado. After insulating and air sealing in the attic I’m turning my attention to the crawlspace that is vented to the outside. There is a a robust vapor barrier in place already. My furnace, ductwork, and plumbing are all in the crawlspace.
I spoke with a contractor yesterday who was adamant that the insulation I use on the inside of the stemwall should be vapor open (mineral wool or a fiberglass blancket). He argued that if the concrete (no damp-proofing) can’t dry to the inside it could result in transferring moisture to the framing. My understanding was that the insulation should be vapor closed (polyiso) so that warm, moist interior air doesn’t condense on the cold foundation wall.
I’d appreciate any thoughts..thanks!
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