I am doing a bathroom remodel in my Central PA home. I have heard several different opinions on how to install a vapor barrier. I was told by one person that I should install unfaced insulation on all exterior walls and then install a 4 mil poly vapor barrier. After that, I should install green board.

Then, I was told by another person that I could just use paper faced insulation behind the green board. I now have 10 sheets of green board, rolls of faced insulation (can be unfaced if I tear off the paper) and have not yet bought the plastic sheeting.

How should this be installed? I have a fiberglass 4 piece shower that can be installed directly on the studs, but should that have a poly vapor barrier behind it but no drywall?

I just want to make sure this is done right, even though I may be selling the house in a few months.

Thanks.

Jim

Your first guy is correct. I would not install the shower directly to the stud wall without drywall. Sound, insulation and overall strength would be better with greenboard.

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Originally Posted by ballengerb1

Your first guy is correct. I would not install the shower directly to the stud wall without drywall. Sound, insulation and overall strength would be better with greenboard.

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I knew I should have taken my time on my question. My shower surround will be screwed into two side walls and an exterior wall. Are you saying I should do green board behind the entire shower surround, even on the interior walls? And on the exterior wall, I should do unfaced insulation, 4 mil barrier and then green board?

Thanks.

Yes, use greenboard on all sides of the shower and even insulate the interior wall, better for sound. Unfaced or paper face showing to interior, either is OK then the 4 mil between the insulation and the greenboard.

ballengerb1,

I was told by one person that I should never use faced insulation and cover that with 4 mil plastic. I talked to a friend last night and he has remodeled several houses in our area and he said they always just used faced insulation and greenbord with no plastic because he said it will sweat and just get the back of the greenboard wet.

Thanks.

The greenboard can handle that moisture which is not sweat, its moisture seeping through your construction materials. Most paper faced insulation is no longer just paper but includes a tarlike substance. I use the 4 mil because it only adds about $3 to the cost of the job and it is 99% non-permeable.

Ok this is it
Use the insulation that you have on all exterior walls and interior walls for sound if needed
Do not drywall behind shower enclosure
Install shower complete
Drywall to shower and over top nailing flang
Never have a double vapor barrier BAM BAM

The real question(s) (part 1 and 2) for Emeril is this... why are you answering shower questions when you have food cooking on the stove? And... why can't you have a double barrier? (Does this create unwanted sweat between a bedroom wall and the bathroom vapor barrier beneath the wonderboard?)
Or... does this really mean you can't create a shrimp jambalya for 50 in the bathtub??
By the way, my favorite cookware is the heavy ribbed Emeril square skillet and the "very" large dutch type heavy cast type stew which I use for everything...
Thanks...