The question has been posed whether plastic sheeting is used as a vapor diffusion retarder (VDR). ABSOLUTELY! There are different types of vapor diffusion retarders- but plastic sheeting is one of the primary ways in which to control the moisture content coming into your home or building. A vapor diffusion retarder is a material that reduces the rate in which water vapor can move through a material such as a plastic sheeting liner or vapor barrier. The ability of a material to retard the diffusion of water vapor is measured in units referred to as "perms. Vapor barriers are also measured in terms of its "permeability". Any material with a perm rating of less than 1.0 is considered a vapor diffusion retarder, or a plastic sheeting vapor barrier.
Some plastic sheeting is more effective as a vapor diffusion retarder. That is because it is engineered to specifically retard the flow of water. Additionally these plastic sheeting liners are tested to the ASTM E1745 standard.
To see all our vapor diffusion retarders for crawlspaces, please click here.
