re: subfloor and floor replacement

quote:

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I'm not sure where the "moisture" is coming from, but the expert assumed it just came up from the ground underneath the house.

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Yep. Back before HVAC, this wasn’t an issue. Once A/C is introduced, that warm, moist air is seeking equilibrium with that cool, drier air in the home, which over the years creates thousand of cycles of this and, inevitably, condensation; then rot.

Closed cell foam can actually mitigate this issue, but you have to fix the ventilation issue. Of course, there’s a trade off, and closed cell can create problems if there’s a leak up above that can’t get out.

Good luck, OP!