Hey guys, this one has me picking my brain a bit.
Yesterday I replaced the bathroom fan/light combo in my gf’s master bath. In doing so, I found that the original fan and the fan from the adjacent bath had both been vented to the soffit with corrugated plastic piping that has seriously degraded. While in the attic, I also found that almost every rafter bay on that side of the roof – south facing with very little sun – has some extent of black mildew/mold present and in some cases, A LOT of it.
The north-facing side is clean. The house is circa 1995 and isn’t exactly what I would call well-built. I’ve chased all sorts of problems already so this isn’t too much of a surprise. Roof is architectural style 3-layer laminated asphalt over felt over plywood. Soffit is run-of-the-mill corrugated vinyl. What I’m seeing for venting is a single 4 foot or so run of vent channel running up from the soffit, terminating to open air. Ridge vent appears to be something similar to CoraVent. There are no gable vents. The attic is insulated – 2×8 ceiling joists with fiberglass blow-in. There are some short bats of fiberglass insulation at the ends of the ceiling joist bays presumably to keep the blow-in out of the soffits. There isn’t a lick of moisture barrier anywhere.
My original thought was simply that the shoddy job of venting the bathroom fans through the soffit had allowed enough moisture escape through the “duct work” and back into the attic, condensing on the cool underside side of the roof and allowing mold growth. That just seems too easy to be the answer though. Also, there is mold along the entire eave – about a 40 foot run. Both ceiling fans are close – within 8 feet of one another and towards the southeast corner of the house.
I hate throwing this all out there, but I’m not too keen on roofing systems and definitely don’t want to let this go. Any thoughts?
Thanks in advance,
Nick
Replies
Bump