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KMARTEL 10-02-2007 08:18 PM

Bathroom exhaust - ceiling damage

This is my first post on the site. I've read through alot of the questions and answers and it looks like a great place to get info.

I live in Winnipeg, Manitoba; that's in Canada EH! During the melt/freeze months i.e. March/April, the drywall around our bathroom ceiling fan gets soft and water dripps on the floor. I went up into the attic today and noticed that the exhaust ductwork is insulated except for a small portion at the very top where it goes thru the roof.

What I think is happening is that the warm air from the bathroom is condensing with the colder attic air and it's causing condensation.

We often hear what sounds like chunks of ice breaking and falling onto the ceiling above for about a week or so. Could it be that the condensation keeps building up on the uninsulated pipe, runs down the angled portion of the duct when warmer outside and then freezes when cold again? Eventually I think the ice buidup on the ductwork falls off and that's what we're hearing.

Am I on the right track here? Can such a small portion of uninsulated ductwork cause this problem? Would insulating this portion stop the condensing issue?

Here's the pictures I took today. Looking to fix the problem before it gets cold out.

Thanks for any help. I'm sure someone is experienced to find a cause here!

morrelld97 10-04-2007 09:21 AM

Some things to think about..

- Are you sure the exhaust is even working? Maybe the soft spot on the ceiling is that the damp air is not pulled out.

I note the attic ceiling does not look discolored. In the past when I have seen the exhaust in the attic with a moisture issue, the ceiling gets discolored or turns dark where mildew has formed.

- But, maybe your hypothesis is correct. It won't hurt to put the insulation all the up to the attic ceiling, perhaps there is some condesation and freezing ocurring on the top of the pipe.

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