I am confused about whether to install a vapor barrier between my sheetrock and stud walls in my bathroom remodel.
All walls in the bathroom are interior. The bathroom is approx. 55 sq ft including shower. There is a skylight and a 2 ventilation fans (one over the shower, and the second over the toilet). I have installed 1.5 to 3 inches of mineral wool insulation around all the walls including the shower for noise suppression. The sheetrock is going to be 1/2″ DensArmor Plus fiberglass based sheetrock for the walls and 5/8″ thick for the ceiling.
I was about to install a sheet of 6-mil plastic around all the walls in order to keep moisture out of the walls, when my plumber, whom I respect, said that he has never seen a vapor barrier installed in the bathroom and suggested I research it a bit more to make sure I’m not going to cause any problems.
What is the correct thing to do?
Replies
I'd say it's optional. If you have a good bath fan (installed properly!!), it will manage/remove moisture. IMO use e.g. cement board for any shower/tub surround that gets water. It's cheap insurance against water damage, is durable, and an excellent substrate for tile.
Use semi gloss paint or other vapor barrier rated paint. How about the ceiling? Is it interior as well? What is your geographic location? That MAY have an affect if you are in the humid south ... someone else might jump in w/ some additional words of wisodm if so.
I can't think of any reason to do so.
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>>>he has never seen a vapor barrier installed in the bathroom
There are plenty of bathrooms with vapor barriers, in some climates it is critical, but they tend to be for exterior walls. Yours are all interior = no need.
Scott.
The reason for installing vapor barriers on exterior walls is to slow down the movement of moisture laden air which will condense if it hits cold surfaces. Unless you have a wine cellar or other refrigerated room adjacent to your bathroom, all the walls will be same temperature and condensation within the wall will not be a problem.
Your shower and/or tub walls should have a 6 mil poly WATER BARRIER over the studs and behind the cement board no matter what the rest of the room has - per TCNA.
Jeff
I'm curious. What is TCNA?
Tile Council of North America - their handbook is 'the Bible' http://www.tileusa.com/publication_main.htm
Jeff
You might want to wade into the discussion in Construction Techniques on "Tiling Down to a Tub Flange". Poly is taking a beating.
"The sheetrock is going to be 1/2" DensArmor Plus fiberglass based sheetrock "
Why not consider DenShield -- similar, but with a waterproof membrane on the surface that's made for tile.
Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.