OK, this is the situation. In the center of the attic, when humidity is high, generally in the summer (Northeast NJ), the floorboards and the ceiling joists become saturated with water. This only occurs in a small area in the center of the attic, far from any windows, right in the middle of the attic floor. This tends to dry out in the winter, but results in moisture damage to the ceiling below.
The roof is tight, no water enters the attic from the outside (confirmed by three different roofers, a home inspector and a structural engineer, all of which had moisture meters and actually sprayed down the roof to create leaks.) The wet area is not anywhere near the chimney. There is no plumbing in the attic at all. No mechanicals in the attic, no drain lines, nothing. Insulation is clear of the soffit vents and there is excellent air flow from them. Homeowner had previously installed all new soffit vents, new windows, and now most recently a roof attic fan with temp and humidity controls.
The new roof fan has been operating for two days now, and what is occuring is the wet area is growing, water actually pooling on the floorboards and joists, and running along them to increase the wet area.
Nobody can figure this out. I'm trying to help a coworker with this problem and the only thing I can come up with to tell her is that the increased air flow is drawing the moisture from the floorboards, wicking it to the surface. She shut off the fan, and I am going to advise her to put it on and leave it running for several weeks to see if this is in fact the case.
She called the manufacturer and they couldn't figure it out, and told her to shut the fan off. I think that they are simply worried about a lawsuit or claim and don't want to get involved so the safest thing is to tell her to shut it off.
Does anyone have any other ideas here?
Thanks to all. RN