Vapor barrior for tiled shower
I’m in the middle of a kitchen and bath remodel right now that I am doing myself. As part of the bathroom I am adding a custom tiled (slate) shower/steam-room that has one outside wall. When I had the building inspector over for plumbing rough-in he told me not to use a vapor barrier on the outside wall in the shower. I thought this was odd but didn’t say anything. When I told this to a relative who does insulation for a living he also thought that it was odd so we put the plastic up anyway.
I live in Minnesota so under normal circumstances the vapor barrier goes behind the drywall. In the case of the Shower/steam-room who is correct? Should I use a vapor barrier or not?
MW
Replies
Use of a vapor barrier in this situation is not as important as NOT using drywall. Are you going to put a custom slate surround over drywall?
I'm not a professional so most of my knowledge is through books and talking to others. What I have are 2x4 outside walls so with the R-13 fiberglass in place and a sheet of 4 mil plastic over the insulation, my next step is to construct the shower pan with a liner. The shower pan will not meet the outside wall as there will be a full length seat in the shower on the outside wall. The seat will be framed with 2x4s and covered with plywood then cement board. I will also be using cement board for the walls and ceiling directly over the vapor barrier. The ceiling meets with attic space so it also has a vapor barrier. Should I use any additional vapor barrier either on the interior walls or the seat or both?
MW
You are.
It's this messed up take on vapor barriors I've seen with building inspectors more than a couple times myself. It's like the inspector is afraid the moisture won't have any place to go- like a nice, dry wall cavity. "mmm, imagine the mould inside that wall and more moisture on it's way! Wonderful!!! I think Homer Simpson would have taken your inspector's job if the one at the nuclear power plant wasn't available!
You need more than a vapor barrier, particularly if it is a steam shower. Water goes through the grout and the cement backer board to the framing members. You need waterproofing behind the backerboard, or even better on top of the backerboard.
Check out the Kerdi system if it is not too late:
http://tileyourworld.com/tile_tools/schluter_kerdi_shower.htm
More on shower construction:
http://www.johnbridge.com/vbulletin/showthread.php?t=5434
Billy
Edited 1/4/2005 8:20 pm ET by Billy
It's not to late, in fact it maybe a couple of months before I'm actually able to do the shower. At this point the shower is framed and the ceiling and outside wall are insulated, the lights are in as well as the drain and I'm working on the water lines.
MW
Kerdi has very good instructive CD-ROMs available to show typical installations for their products. Check with your tile supplier; he might have a copy on hand or should be able to get you one.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?