Hi - We recently remodeled our home, replacing the entire roof (with trusses) and creating an uninsulated loft/attic. We had blow-insulation put in between the joists which was then topped with 1" plywood flooring. After a year, we noticed some condensation on the floor on cold winter days (cold as in 10 or so degrees F) which eventually caused some water staining on the floor. After some investigation (pulling up some flooring) we found that mold was growing in the space between the ceiling of the first floor and the loft flooring. There was mold in the insulation and on the wooden joists. We checked the ductwork which was fine. So the problem seems to be condensation in this space caused by temperature differential. The house has no other humidity or mold issues.
So what to do? Our contractor has been looking around for a good solution to this problem. He says that if it was new construction, they'd have used a vapor barrier against between the drywall ceiling and the joists but this cannot be done at this point. One solution he's looking into is using foam insulation and possibly coating the joists with something to prevent mold growth. Will this work? Does anyone else have any ideas?