Unvented, sealed crawlspace under pier foundation
We’re in western Montana — cold, dry, very little humidity and rain, decent amount of snow. Bought a small house (< 700 sq. ft.) on a pier foundation. The crawlspace is raised about 40 inches above grade. The floor joists were insulated with fiberglass batts and covered with thin plywood. Unfortunately the plywood didn’t cover things completely, because rodents were living in the insulation between the joists. They had all kinds of tunnels, nests, etc. I’m in the process of cleaning all that out and tearing out the old batts. I’m wondering if I can make the crawlspace sealed and unvented and insulate with rigid foam on the outside skirting walls, following the recommendation of GBA’s unvented crawlspace article? The only reason I’m questioning this is because that article and other sources of the technique all seem to refer to traditional crawlspaces, rather than pier foundations that sit above grade so much. I would much prefer to insulate the walls, rather than the floor joists, because it’ll cost me less (less wall coverage than floor), it’ll be much easier, and I’ll be able to get the air sealing details done right. Feel free to point me to any reference articles if they exists. Thanks all.
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