Vapor Barrier Under Epdm Roof

In a low slope roof assembly the vapor retarder is normally installed under the primary roof insulation.

Vapor barrier under epdm roof.

This vapor if left unchecked can wet the insulation and over time will reduce the r value of the insulation and lead to mold. 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. Air vapor and water barrier products for all six sides of the building envelope 3. The vapor barrier protects the roof insulation from the vapor included in the interior air.

The roof is a large part of the building envelope and therefore has a significant impact on the flow of energy in and out of buildings. Vapor control membranes play a very important role in this. Numerous roof components work together to affect a building pages. Typically a vapor retarder has to have a perm rating of 1 0 or less to be successful.

A vapor barrier can be loose laid or fully adhered. A roof design that includes an adhered roof membrane with multiple layers of insulation with board joints offset and staggered over a vapor retarder air barrier helps lower the risk that air and the moisture it carries will infiltrate the roof system. Laps shall be fully sealed in an application of hot bitumen. Side laps shall be minimum 100mm 4 wide and end laps shall be minimum 150mm 6 wide.

1 2 3 filed under. That reduction of air and moisture infiltration can then help improve roof longevity. Attention roof system designers. But in un vented roofs in hot humid climates the authors argue that water from the roof surface is drawn upwards in liquid form by capillary action between plies of overlapped shingle courses where it passes ultimately through the vapor barrier and through the roof decking to the roof cavity interior.

When re roofing apply one 1 ply of no. Everyone knows that water in roof systems is never a positive. A loose laid vapor barrier is just a big sheet of 6 mil plastic that is. 15 organic felt adhered in a full application of hot asphalt applied at the approximate rate of 1kg m2 20 lbs 100 sq.

A vapor retarder is commonly installed on the warm interior side of a roof or wall.