The difference between waterproof breathable membrane and vapor barrier membrane

The mode of action is different: the waterproof breathable membrane is mainly a functional material laid on the top of the insulation layer. The function of this material is to prevent outdoor rainwater from entering the insulation layer. However, the vapor barrier film is a kind of protective film used as a vapor barrier layer, and this protective film is generally in the lower layer of the thermal insulation layer. One acts on the top of the thermal insulation layer, and the other acts on the bottom of the thermal insulation layer, so the methods of action are different.

The basic functions are different: the main function of the waterproof breathable membrane is to prevent rainwater from entering the insulation layer, and it can also discharge some moisture generated in the insulation layer to the outside, which can keep the insulation layer dry for a long time. However, the waterproof breathable membrane plays the role of moisture-proof and vapor-proof, which can effectively prevent indoor moisture from penetrating into the insulation layer.

The basic effects are different: the waterproof and breathable membrane has a strong protective effect on the insulation layer, so it will not affect the service life of the insulation layer. However, the thermal insulation effect of the vapor barrier film is different, which will affect the service life of the thermal insulation layer.