MiamiCanes
New Member
Over the past few days, I've come to the conclusion that the bathroom exhaust fan's duct is almost certainly letting water into the wall. I don't have a 32-foot ladder & can't get up on the roof to easily check, but I'm guessing that it has either leaking flashing or no flashing at all, and might very well be missing the "tophat" above the duct itself as well.
The duct itself is a 3" diameter flexible metal duct. It has at least 3-6" of vertical "play" (the duct itself as a whole, not expansion of its accordion joints; I didn't pull on it terribly hard to test the true limits of its vertical motion for obvious reasons). It enters the bathroom inside an interior wall through a hole in the concrete (cast in place, steel pan deck) roof above.
When I bought the house, I discovered that the duct was blocked, and had been blocked for a long time. A few days ago, when I started removing the bathroom's old, moldy drywall, I bought a vent cleaning brush and proudly cleaned it out. At the time, big chunks of asphalt roofing material came out. I was disgusted, thinking that some careless roofers dumped tar & gravel into it when they re-did the roof (~10 years ago, from what the seller told me when I bought it). It occurred to me this morning on my way to work that the roofers might have intentionally covered the whole duct because it was leaking, and I might have successfully punched a bigger hole in the roof (regardless of their motives for doing it, recent water infiltration definitely seems to have been happening anyway). Oops.
The evidence of recent water damage is overwhelming. The back of the drywall on the OTHER side of the wall (I ripped out the drywall on the bathroom side) doesn't feel damp, but LOOKS like it's been soaked on a regular basis over the years, is hosting a thriving mold colony, and has a moisture reading of 10-11% (I bought a 2-pronged moisture reader a few days ago). By contrast, other walls nearby have moisture readings of 4-5%.
Anyway, I think it's safe to say that the exhaust duct needs to be rebuilt -- probably replaced with a 3" PVC pipe that's firmly fastened to the studs (for strain relief), with new flashing, waterproofing, and something at the opening to keep rainwater out. Does anybody have any idea what I'm looking at cost-wise if I hire someone to do it? Is this a project I could viably do myself if I somehow got a hold of a 32' extension ladder (so I can get on the roof)?
The duct itself is a 3" diameter flexible metal duct. It has at least 3-6" of vertical "play" (the duct itself as a whole, not expansion of its accordion joints; I didn't pull on it terribly hard to test the true limits of its vertical motion for obvious reasons). It enters the bathroom inside an interior wall through a hole in the concrete (cast in place, steel pan deck) roof above.
When I bought the house, I discovered that the duct was blocked, and had been blocked for a long time. A few days ago, when I started removing the bathroom's old, moldy drywall, I bought a vent cleaning brush and proudly cleaned it out. At the time, big chunks of asphalt roofing material came out. I was disgusted, thinking that some careless roofers dumped tar & gravel into it when they re-did the roof (~10 years ago, from what the seller told me when I bought it). It occurred to me this morning on my way to work that the roofers might have intentionally covered the whole duct because it was leaking, and I might have successfully punched a bigger hole in the roof (regardless of their motives for doing it, recent water infiltration definitely seems to have been happening anyway). Oops.
The evidence of recent water damage is overwhelming. The back of the drywall on the OTHER side of the wall (I ripped out the drywall on the bathroom side) doesn't feel damp, but LOOKS like it's been soaked on a regular basis over the years, is hosting a thriving mold colony, and has a moisture reading of 10-11% (I bought a 2-pronged moisture reader a few days ago). By contrast, other walls nearby have moisture readings of 4-5%.
Anyway, I think it's safe to say that the exhaust duct needs to be rebuilt -- probably replaced with a 3" PVC pipe that's firmly fastened to the studs (for strain relief), with new flashing, waterproofing, and something at the opening to keep rainwater out. Does anybody have any idea what I'm looking at cost-wise if I hire someone to do it? Is this a project I could viably do myself if I somehow got a hold of a 32' extension ladder (so I can get on the roof)?