I've got a problem with my home that I've had since it was built. When it rains, slowly and steadily, or the wind is blowing from the right direction, I get a lot of rain water in the bathroom fans. All of them - even the one in the laundry room. I've sealed up all around them, and I don't think the roof is leaking. I think it's coming in through the vent. The roof is low slope - 3 in 12 - and I wonder if that has something to do with rain splashing up into the vent. I'm thinking of replacing all the vent fans, but don't know if that will fix it, or if there is a special type of vent hood I need for a shallow pitch roof. Anybody seen anything like this before? Think new vent fans would work? Thanks!
I don't know how much water is "a lot", and I don't know what region you live in, and I don't know if your exhaust fans have metal ducts to the outside, but is it possible that the problem is condensation in the ducts? Or maybe the vents need backdraft dampers.
Architect (NY) and Home Designer (PA)
I'm in Colorado, so it get's pretty cold in the winter, and yes, I have condensation problems then - a nice layer of frost on the inside of the vent that defrosts and melts shortly after I turn on the fan. However, this is condensate from the house, not from the outside - outside air is pretty dry here. But the real problem is the water that comes in when it rains. "A lot" to me is enough to need a bucket of some sort to keep the carpet from getting too wet - probably 4 oz during an evening of rain. Interesting to note that snow on the roof doesn't cause a problem - it only leaks while rain is falling. Forgot to mention that I have cathedral ceilings, so the distance from fan to outside is quite short - 12" total, I believe, and there is a short metal duct for that distance.
Thanks for any insight.
Well, that's probably more water than would condense in your duct during a rain. Is there any sort of backdraft damper in the duct or ar the outlet? If so, maybe they are stuck, or rusted, and don't close properly. What do the vents look like? Are they raised above the roof so that windblown rain will blow under and past them?
Architect (NY) and Home Designer (PA)
I have never been on a message board before. If I can I would like to tag onto Neill's post from 2007 and find out what the answer was. We have the exact same problem. We have two bathroom ceiling vents on the top floor of our house and both leak a lot but only during heavy rains with hard winds. Our roof has a 30 degree pitch. My husband was just up in the attic and the roof deck is fine, not wet or damaged in any way. He did clean out quite a bit of wasps nests that were sitting at the front of both vents. The outside flap that covesr the tubing and let the humid air outside when the fan is on is also fine.
Now that the wasp nests are gone, Are you still having the leak issue when it rains?
Ideally although not practical in some cases is the fans should vent out sidewalls or out over the soffits to prevent this exact issue your having. Any time you cut into a roof you chance a roof leak.
So if the leak continues you can either, Close off the vent and go elsewhere for the vent, or change the roof vent with another model that perhaps works better.
In any case you should make sure that what ever type of vent location you choose that the vent pipe be insulated to prevent condensatin from forming in the pipe during use in the winter.
We are selling our house so I'm afraid to test it intentionally. We were gone when this happened this time but typically we turn the fans on in the bathrooms and this prevents it from leaking in.
So trying to minimize our cost (since we are selling) and still solve the problem for good, is there any other option that comes to mind or maybe can you recommend a vent that would not allow the water to blow in on a 30 degree roof pitch?
Thank you for your help.
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