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  1. #1
    Join Date
    Dec 2009
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    Question Bathroom exhaust fan drips water

    We have a bathroom exhaust fan that condensates or drips water. The hose for the fan goes to the roof through our attic. Any ideas on what would cause this to happen?

  2. #2
    Join Date
    Mar 2009
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    1,387

    Default Re: Bathroom exhaust fan drips water

    Hi, It can be can just be condensation... Is there a vent stack pipe cap on the pie that sticks out threw the roof? Is the vent exhaust pipe insulated?
    Years ago in Colorado i simply installed a longer exhaust pipe and looped it in the attic= no more drip as it was simple condensation...

  3. #3
    Join Date
    Dec 2009
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    2

    Default Re: Bathroom exhaust fan drips water

    Thanks for your reply. And no it is not insulated. We will give it a try.

    Thanks Janet

  4. #4
    Join Date
    Dec 2009
    Location
    Casper, Wyoming
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    159

    Default Re: Bathroom exhaust fan drips water

    Installing some flexible duct material will help stop the condensation. The change in temperature between the bathroom and attic-roof is probably causing the condensation. They sell it at all the big box home improvement stores.

  5. #5
    Join Date
    Jan 2010
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    3

    Default Re: Bathroom exhaust fan drips water

    Warm air with some humidity will be rising through the vent pipe all the time, when the fan is off too.
    Is your home unusually humid during the winter -- humidifier going, lots of boiling style cooking, etc. (?)

  6. #6
    Join Date
    Feb 2010
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    1

    Default Re: Bathroom exhaust fan drips water

    I just want to ask if the bathroom's in-wall exhaust fan exhausting directly through wall? If that happens, I would recommend that you should check the attic and see what is really happening. If water isn't evident on the exterior of the vent pipe, then it isn't the flashing. Bathroom Fan
    Last edited by lauretta07; 02-23-2010 at 01:30 AM.

  7. #7
    Join Date
    Aug 2007
    Location
    The Great White North
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    4,045

    Default Re: Bathroom exhaust fan drips water

    Quote Originally Posted by Marcy Tate View Post
    Installing some flexible duct material will help stop the condensation. The change in temperature between the bathroom and attic-roof is probably causing the condensation. They sell it at all the big box home improvement stores.
    I suggest if you are posting to try and promote your internet service you should get your information correct.

    For all we know that could mean the crappy white plastic flex duct that many folks already use.

    A bath exhaust fan when used during showers is blowing out warm 100% humidity up through the ducting in the attic and out the roof.

    When the attic is cool or freezing cold that humidty is condensing and may be freezing inside the ducting --- regardless of the ducting --- metal or the white plastic flex --- if it isn't insulated .

    Consider when the duct is vented out the roof it's running vertically ---- more or less straight up ---- so any water from the condensation will run back down and drip from the fan.

    The duct should be insulated along the entire run in the attic to minimize the warm humid air being exhausted to condense.

    As also mentioned earlier---- when the fan is not being used warm air may escape up the exhaust fan duct and also condense. One way to minimize this is to check the backdraft damper is present and functioning ---- ideally a spring loaded type is best.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  8. #8
    Join Date
    Feb 2015
    Posts
    1

    Question Re: Bathroom exhaust fan drips water

    I had new fans installed in the bathrooms recently (Start of Winter). Both are rated as more than adequate for the size of the bathrooms. New vent pipes were also installed directly through the roof and appear to working properly. I can see the vents open from outside. The contractor insulated the pipe in the attic but we still get a great amount of dripping from the fan and the water collects in the cover and stains the ceiling next to the fan.
    The contractor has been out several time and he is telling me our water is too soft and creating too much steam. Have you ever heard of that? He wants to have a water consultant visit to adjust the water softener unit.
    Thanks,
    Sushi

  9. #9
    Join Date
    Aug 2007
    Location
    Portland, Oregon, formerly of Chicago
    Posts
    1,808

    Default Re: Bathroom exhaust fan drips water

    Soft water causing dripping! That's a hoot! Your contractor is doing a tap dance.

    As others have said, make sure the dampers are closing properly after use.

    There are humidity sensing switches which will keep the fan running until the humidity has come down to normal. There are also timers which will keep the fan running for a few minutes after the bath has been vacated.

    I would consider a short section of horizontal vent ducting before the verticle rise to the roof exit. A completely verticle pipe will dump any condensation coming down directly onto ceiling. Some horizontal duct will give it a possibility of being evaporated again and sent up the duct.

    During really cold weather in Chicago, I got in the habit of letting the furnace fan run constantly during my shower time. Inside house humidity is very dry when it very cold outside.. This helped humidify the house while dragging the really high humidity out of the bath.
    Last edited by ordjen; 02-20-2015 at 10:33 PM.

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