What materials are commonly used for vapor barriers?

Polyethylene sheets and foil-faced insulation are commonly used as vapor barriers because they are effective at preventing moisture from passing through them. Polyethylene is a plastic material that is highly resistant to moisture, making it an excellent choice for limiting vapor diffusion in building assemblies, particularly in areas where controlling humidity is crucial. Foil-faced insulation, on the other hand, has a reflective surface that not only serves as insulation but also acts as a vapor retarder, enhancing its effectiveness in moisture control applications.

Using vapor barriers made from these materials helps mitigate issues such as mold growth, corrosion, and structural damage, which can occur when moisture permeates walls and ceilings. The effectiveness of a vapor barrier relies on its material properties, thickness, and placement within the building envelope, which are adequately fulfilled by polyethylene and foil-faced insulation.