We have a corner of one room where the carpet constantly feels damp. The dampness starts at the north side wall, runs about 6 feet along the east wall, and about 4 feet into the middle of the room. We've looked at the floor beneath that room from the unfinished basement, and there does not appear to be any signs of of water from below. There is a bay window on the north wall where occasionally the ceiling in the bay gets water spots if the gutters are full, but other than that we cannot see any sign of water entry into the room. Does anyone have any suggestions for finding this hidden water source? When we first started noticing it, we thought it could be the dog, but when looking at the carpet with a black light, it does not appear to be urine.
Bay window roofs are notoriously hard to do properly. Those 'water spots when gutters are full' are sign of problem. They are NOT OK, they should not be there no matter how much it rains. If bay ceiling gets water, you also likely got wet insulation in the wall, and wycking into carpet. I'd open the north wall and check for damage before your framing starts rotting.