Roof Vapor Retarder

Sopra vi is composed of a proprietary formulation of bitumen and is reinforced with a high quality random glass fiber mat.

Roof vapor retarder.

Gaf sa vapor retarder is composed of a proprietary formulation of elastomeric styrene butadiene styrene sbs polymer modified bitumen in combination with a high tack self adhesive. The topside and underside are. When we use a vapor retarder in a roof system it will also act as an air barrier as long as it is sealed at all perimeters and penetrations and is tied to the wall air barrier. Everyone knows that water in roof systems is never a positive.

A vapor retarder is a material or system that is designed as part of the roof system to substantially reduce the movement of water vapor into the roof system where it can condense. In a low slope roof assembly the vapor retarder is normally installed under the primary roof insulation. Sopra vi is a bitumen coated base sheet for use in approved built up roof assemblies. The need for use and design of a vapor retarder in the design of a roof system used to be a hotly debated topic.

A vapor retarder is commonly installed on the warm interior side of a roof or wall. Typically a vapor retarder has to have a perm rating of 1 0 or less to be successful.