Suggestions for insulation on ceiling of wet crawlspace?
For a super insulated house being extensively retrofitted in South Jersey(r40 walls, r70 attic, triple pane windows) with a permanently wet crawlspace (riverfront, high water table), I am considering insulating the ceiling of the crawlspace. Possibilities include 1 inch spray foam (not the first choice due to high cost and high ), 1 inch of polyisocyanurate (Thermax) stapled to floor joists, taped and 6 inch of unfaced fiberglass batts in the floor cavity, fanfold (High-density EPS?) stapled to floor joists with 10 inches unfaced fiberglass, sheet plastic stapled to floor joists with 10 inches unfaced fiberglass.
Every effort has been made to contain the water problem and it is not as severe as an underground stream, but the house will always have some water penetration. In the past (before I bought the house), the water created some mold in the basement (though not severe), and ruined the fiberglass stuffed in the joists.
Though the building inspector recommends against it, I will probably seal the crawlspace vents in the summertime.
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