overly damp bathroom

[deerefan]

I've been fighting this since we bought our house 3 years ago. Both bathrooms, the master especially, retains a lot of dampness on the ceiling, especially in cold weather, which in turn allows mildew/mold to grow freely. I installed a vent fan in the master bath that does a good job of removing steam but does nothing for the ceiling dampness. The master bath has a window where as the guest bath does not, which lead me to rule that out as a possible factor. I've gone as far as buying a dehumidifier, which works but I should not have to use it under normal circumstances. Anyone else have this problem and how do you fix it?

 

[Podunkadunk]

Bathroom Tips and Resources from Improvenet. Find A Contractor.

It's not a lot of help and you seem to have done most of what they recommend, but at least it lets you know that you aren't alone.
-Podunk

 

[voodoo]

Deerfan.
I deal with these problems every day in my line of work as a building surveyor for a housing insurer. Mildew and mould problems have increased exponentially in recent years as houses become more airtight and insulation requirements increase.
Have you checked if there is any insulation above the ceiling. Condensation and mildew will always migrate to the coldest surface available.

I have a publication from work which I'll scan and send to you later. It gives some useful advice.

 

[deerefan]

that would be a great help....we are thinking alike...the house was built in the early 60's and the insulation is original. I've been thinking of having a nice layer of blow-in insulation put on top, even with the top of the ceiling joyces. The roll out stuff is looking a little thin.

 

[voodoo]

Here's the information I promised.
We send this booklet out to any new homeowner who contacts us with a mildew problem.
I am based here in the UK, but the information is relevant anywhere.

 

[BillG_in_TX]

I've been fighting this since we bought our house 3 years ago. Both bathrooms, the master especially, retains a lot of dampness on the ceiling, especially in cold weather, which in turn allows mildew/mold to grow freely. I installed a vent fan in the master bath that does a good job of removing steam but does nothing for the ceiling dampness. The master bath has a window where as the guest bath does not, which lead me to rule that out as a possible factor. I've gone as far as buying a dehumidifier, which works but I should not have to use it under normal circumstances. Anyone else have this problem and how do you fix it?

I read something recently which seemed authoritative (probably because it confirmed what I already do), that stated that you need to run the bathroom exhaust fan for 10 or 15 minutes after you finish your shower. This is necessary in order to remove all the residual moisture that you can't see.

Adding insulation to the ceiling sounds like a good plan, too.

 

[voodoo]

Bill,

You are quite right.
Running the fan for 20 mins after showering etc is more important than during. Most bathroom fans are 4" (May be different in US). They are incapable of effectively removing a roomful of moisture laden air whilst the shower is being used.

Modern fans have a 20-30 minute adjustable over-run and are controlled off the lighting switch. When you turn off the light they continue to extract for set time , then switch off themselves.

Unfortunately, if these are installed in an en-suite situation, most homeowners isolate the fan as there is nothing worse than getting up to the bathroom in the middle of the night, then not getting back to sleep for a fan droning on for 20 minutes. ;-)