Vapor Barrier For Bathroom Walls

The inner surface in colder climates and the outer surface in hot humid climates.

Vapor barrier for bathroom walls.

Vapor retarders are there to slow the diffusion of moisture so the building inspector is off base argues senior editor martin holladay. The vapor barrier should be on the inside between the insulation and drywall. 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. Vapor barriers are usually best installed on the side of the wall that experiences the hotter temperature and moister conditions.

It s usually a thin layer of plastic that sits between the drywall and the studs. There is no need to vapor barrier the non exterior walls. If the tub shares this exterior wall i would put vapor barrier behind it if you can as the plastic tub surround will not give you a vapor barrier i don t think. Between tub and shower sinks and toilet a bathroom has a high potential for water damage not only from leaks of liquid water but also from water vapor that can collect inside exterior walls and condense.