Vapor Barrier Shower Wall Tile

But most residential showers don t generate enough water vapor to be problematic.

Vapor barrier shower wall tile.

Either a vapor type barrier behind the board or a waterproofing membrane on the front. In a shower situation you recognize it as steam. This can take the form of a sheet membrane or a paint on liquid. A vapor or moisture barrier is a layer of protection that is designed to act as a waterproof shield helping to keep condensation away from wood insulation and other mold prone materials that are located behind the drywall.

Moisture barriers stop that. Tile is laid onto the cement board with thinset mortar or mastic. In this highly convenient inexpensive and popular application a moisture barrier of 4 or 6 mil thick plastic is installed directly over the wall studs. Water vapor is water in a gas form.

A seam in an acrylic shower or a cracked grout joint or some missing caulk in a tile shower are all that is needed to let moisture get behind your shower enclosure. If you re using greenboard or drywall for the walls of the shower you ll need to put the vapor barrier between the greenboard and the water. It s usually a thin layer of plastic that sits between the drywall and the studs. You have several options to choose from when choosing a vapor barrier and each affects your waterproofing strategy.

This will be thick enough to hold the moisture effectively. First you have vapor barriers that are installed behind your tile substrate common materials that are used due to their availability and cost are a continuous plastic sheeting with a minimum thickness of 4 mils 15 lb or 15 felt paper some building codes require a minimum grade b building paper to qualify as a vapor resistant barrier. Steam stays in a gas form until it cools down or hits a barrier such as a shower door tile ceiling or a mirror. Screws secure the cement board to the wall studs.

Failure to do that will mean that moisture will soak the greenboard and it will gradually crumble as will your shower wall. In a shower you can t have the vapor barrier on top of the greenboard. A good vapor barrier should be 10 to 15 millimeter polyethylene. This is especially important in a shower located on an outside wall but also helps even if the shower is on an inside wall.

Water vapor that gets behind walls or travels up through light fixtures or hvac grilles into an attic will turn back into water when it cools off. But they do generate enough water to need moisture management. If you have a steam shower with a steam generator then a vapor retarder is required. In the world of tile you need a vapor retarder when you have extreme amounts of water vapor that need to be managed.