What is the purpose of vapor barriers in basements?

Vapor barriers serve an essential function in maintaining the integrity of a building's structure, particularly in areas like basements that are prone to moisture problems. The primary purpose of a vapor barrier is to prevent moisture from penetrating into the living spaces from the ground or surrounding environment. When moisture seeps into basements, it can lead to various issues such as mold growth, wood rot, and deterioration of materials like drywall and insulation. By installing a vapor barrier, the risk of these moisture-related problems is significantly reduced, which helps to protect both the health of the occupants and the durability of the structure.

Vapor barriers do not provide structural support, insulation, or aesthetic enhancement; their focus is specifically on moisture control, which is critical for ensuring that building materials remain intact and the living environment stays healthy.