Damp fiberglass batts in crawl spaces near the creek
Why it happens here
Warm moist air from the house hits a cold rim joist and condenses, and the fiberglass batts sitting against it soak up that moisture. Once wet, they lose most of their R-value and start growing mold.
Our approach
We remove the wet material, dry and treat the framing, then seal the rim with closed-cell spray foam or taped foam board so the moist air never reaches a cold surface again.