Vapour Barrier For Warm Flat Roof

The notion behind a vapour control layer is to install it on the room side of the insulation so it stops the passage of warm moist air entering the structure.

Vapour barrier for warm flat roof.

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. The vcl is easier to maintain in a warm roof construction as it s generally out the way of the dangers of plasterboard fixings and downlighters. Vapour control layers at roofing superstore our choice of flat roof materials includes everything you need to create a long lasting weather proof flat roof that performs and looks good too. The history of cold climate vapor barriers itself is a story based more on personalities than physics.

Vapor barriers are also a cold climate artifact that have diffused into other climates more from ignorance than need. A vapour control layer helps you shield your building from the consequences of condensation. A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation. Rose 1997 regales readers of this history.

It is frightening indeed that construction practices can be so dramatically. The buildup of a warm flat roof starts with a good vapour barrier followed by insulation then more decking or just the roofing materials depends on if you want the roof soft or solid. That reduction of air and moisture infiltration can then help improve roof longevity. If it is not a habitable space or as per the old design for flat cold roofs then you would use foil backed plasterboard which acts as a vb.

Much like the cold roof it stops the transfer of warm moist air from inside the building into the warm roof layers. Often the vcl in a warm roof is bonded to a timber substrate which helps the integrity however in a warm roof the vcl has two important functions. Condensation is generated when warm moist air rises and condenses into a liquid on contact with the cooler areas above the insulation.