Vapor barrier
ANY MATERIAL USED TO RESIST DIFFUSION OF MOISTURE THROUGH WALLS, FLOORS, CEILINGS, OR ROOFS
Vapor barrior; Vapour barrior; Vapour barrier; Vapour barriers; Moisture barrier; Steam barrier
A vapor barrier (or vapour barrier) is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling, or roof assemblies of buildings to prevent interstitial condensation and of packaging. Technically, many of these materials are only vapor retarders as they have varying degrees of permeability.