Roof Vapor Retarder

Typically a vapor retarder has to have a perm rating of 1 0 or less to be successful.

Roof vapor retarder.

This eliminates the need for a separate air barrier that could potentially prevent the moisture from escaping. 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 need for use and design of a vapor retarder in the design of a roof system used to be a hotly debated topic. 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.

The topside and underside are. 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. Sopra vi is a bitumen coated base sheet for use in approved built up roof assemblies. Gaf sa vapor retarder is an sbs modified bitumen vapor retarder for use in approved gaf roof assemblies.

In a low slope roof assembly the vapor retarder is normally installed under the primary roof insulation. A vapor retarder is commonly installed on the warm interior side of a roof or wall.