Home>Discussions>INSULATION & HVAC>How to tackle serious damp in the bathroom?
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How to tackle serious damp in the bathroom?

I have recently bought an old cottage, and the main part of the cottage is fine, but an extension build in the 60s suffers from damp. The bathroom is in this extention, and damp is literally running down the wall (the outside wall) - this isn't very pleasant and I need to deal with it before it ruins stuff in the bathroom and maybe even has health implications... we already have a fan in there and when not in use, the door is almost always open. We're even careful about how long we stay in the shower (there is no bath) so that it doesn't get too steamy...

Timothy Miller
Re: How to tackle serious damp in the bathroom?

Howdy, consider checking the roof above the wall( if one story roof ) that has wettness running down it. Sometimes a hole in the roof can have water run down an show up on the inside and or outside wall. Does the wall have insullation? Which direction is this wall- North? Is the shower head on this wall? I ask becasue i have seen freeze damage break in the supply pipe that only leaks when the shower is on. The spry may be again show on the outside wall...

Re: How to tackle serious damp in the bathroom?

I agee with Timothy---could you also post the cfm output rating on the bathroom fan & the dimensions (L X W X H) of the bathroom---can you see & feel air being exhausted from the fan when you hold a piece of tissue paper near it---is the vent piping on the fan working ok???

Re: How to tackle serious damp in the bathroom?

I've had some similar problems in my bath. Knowing the following would help: Does the addition have a basement, or a crawl space? Is the exhaust fan vented into the attic space, or outside? Are your exterior walls insulated?

If you have a crawl space, make sure that its dry. If not, you can have a company that specializes in dealing with wet basements come in and install a crawlspace liner and ventilation system. If you are in a cold climate, add insulation to the exterior walls and attic. And make sure the exhaust fan is venting to the outside and the vent hose is properly insulated. Good luck!!

Re: How to tackle serious damp in the bathroom?

my number 1 choice is that the exterior walls are either not or are poorly insulated. a cold wall + instant heat from the shower = visible moisture on the walls. just like ice water in a glass on a hot humid day. if you check your insulation and then insulate as needed and then buy a nice new high cfm vent, i bet you'll be in good shape.

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