The vapour barrier resists the diffusion of water vapour from the inside to the outside of the building envelope. It protects the insulation and structure from moisture damage that can be caused if water vapour moves into and condenses in the envelope assembly. In some applications, the vapour barrier also acts as the air barrier by reducing heat l [..]

Paint, plastic sheeting, floor or ceiling material specifically designed to minimise the migration of humidity into or out of a room.

A membrane used to prevent moisture from penetrating a wall, roof or floor; also a wrap to prevent the escape of condensed water from cold pipes or ducts.

A material, typically a plastic or foil sheet, that resists diffusion of moisture through wall, ceiling and floor elements.