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.

Vapor barrier for bathroom walls.

It s usually a thin layer of plastic that sits between the drywall and the studs. 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. The inner surface in colder climates and the outer surface in hot humid climates. 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.

The vapor barrier should be on the inside between the insulation and drywall. Normally interior walls do not require a vapor barrier but there are some situations where it is highly recommended. There is no need to vapor barrier the non exterior walls. In existing spaces oil based paints or vapor barrier latex paints offer an effective moisture barrier.