I am renovating bathroom which has a seperate 4×8 room for the toilet and shower. There is no door to the room, only a 32 inch cased opening and the rest of the bathroom is a 8 x 8 room for the vanity. The room for the toilet and shower has no windows, but it has an exhaust fan vented to the outside. The drywall on the walls and ceiling of this room show signs of water beading up on them in excessive amounts, the owner has tried various mildew resistant paints and has not had any luck stopping the water staining and mildew. We are gutting the bathroom and installing moisture resistant drywall in the room. I dont think this will solve the problem. The walls in question are on the exterior of the house. There is tyveck installed directly on the studs, and T-111installed on the tyveck, then vinyl siding. Could the Tyveck on the studs be trapping moisture?
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Replies
Probably not.
any insulation involved here?
No - he has exccessive moisture and inadequate insulation
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The problem is lack of insulation and possibly a poor job of sealing the Tyvek. The walls get cold due to air infiltration and encourage moisture to condense on them.
He should have a timer or humidistat on the exhaust fan.
Could the Tyveck on the studs be trapping moisture? No
No insulation plus cooler weather = cooler interior surface = perfect surface for condensation.
Do they use the exhaust fan? Is it sized correctly?I would think that situation would call for a 100cfm min. Since there's little or no insulation they should be turning on the timer switch for the fan as soon as they go into the bath, then let it run for a good 10-15 minutes after the're out of the shower.
As already said, fan switch with timer....then use it!..... lot easier than a full gut
Geoff
When you demo'd that wall did you notice any signs of water leaking into that cavity? Or even a gap in the T - 111 which would be allowing cold air to enter? How about the roof, is there a valley over that spot which might be leaking?
Sounds like the house was built improperly to begin with (no plywood) and this is what happens when you cut corners
No leaks from the roof. The house was actually built by an architect as his personal home approx 12 years ago. We put the vinyl siding on about 3 years ago and were surprised to find that there was tyveck on the studs.
Edited 3/1/2008 6:58 am ET by Captndestructo
Why were you surprised to find the Tyvek???
If your view never changes you're following the wrong leader
I had never seen tyveck directly applied to the studs before. Is it a common practice?
Well, you wouldn't put it on the outside of the T111.Not common practice, but it's done.
If your view never changes you're following the wrong leader
What is the situation with the insulation? You didn't say....
Also, perhaps the bath fan is undersized or the outlet ducting is constricted to where enough air isn't being moved out. The occupants say they use the fan - but who knows what really happens. Maybe there is a teenage daughter or someone who likes to take 20 minute showers and doesn't like the fan noise. Hook the light up to the timer suggested above. Then there won't be any question about whether the fan is being used.
The problem is probably caused by a combination of things...
Insulation is adequate. Fan was being used by occupants. Today electrician removed fan to install new fan. Flapper leading to flexible vent was stuck shut. Fan was running but not removing any steam. Hopefully problem solved.
That would 'splain a lot of the problem.
JimNever underestimate the value of a sharp pencil or good light.
Sounds like the house was built improperly to begin with (no plywood) and this is what happens when you cut corners
T-111 is plywood... with a 'finished' face. The 'finished' part is debatable. I'm no fan of T-111, but it is in no way a contributor to the problem at hand. It is serving an identical function as plywood in this situation.View Image