We had spray foam installed in the rim joists and between the floor joists above the crawl spaces in our Cape house last Fall. The original house was built in 1758 but the problem appears to be in the 1970's addition. I was picking up kid toy clutter and moved a box of toys by one of the fake antique beams in the room, and found this (see pic). It's gray and fuzzy. The only thing that we've changed in the house since last year is the insulation. The first winter/summer we were here, we saw no mold. No idea about the hard line at the bottom - there was nothing against the beam, just a toy box (no mold) near the wall. Thoughts? Help?