Template:All systems - VAPOUR RETARDERS

The decision to use, and the selection of, an air/vapour retarder is the responsibility of the design authority. Neither RGC nor the roofing contractor will accept any responsibility for damage to, or failure of, the roof system caused by the use or absence of a vapour retarder.

Vapour Retarder Design for High-Humidity Building Interiors

RGC recommends that when design authorities specify roof assemblies over high-humidity building interiors that careful consideration is given to the type and construction of the vapour retarder.

Because great amounts of moisture are released into interior environments of high humidity buildings [swimming pools, commercial laundry facilities, large aquariums, paper mills, etc.] there is a high degree of risk that extreme amounts of moisture will accumulate within the roof assembly when an effective vapour retarder is not included.

Vapour retarders for high humidity facilities should have a perm rating as close to zero as possible, be durable, multi-layer membranes that are effective in preventing vapour drive into the roof systems from the interior of high humidity environments.

Thin, lightweight, single-layer vapour retarders are prone to damage during installation of roof assemblies and are therefore not recommended for use over high humidity building interiors.