Primers as surface preparation are an intricate part of any fluid applied roofing and waterproofing system. Their fundamental purpose is to not only provide adhesion to a particular substrate or existing roof system but also act as a vapor barrier between that substrate and the new fluid applied system to ensure limited moisture migration from the underlying substrate or existing roof system. Unchecked moisture migration from the underside could lead to delamination of the new fluid applied system.
RMI primers have been formulated for specific applications and substrates. RMI requires both moisture & adhesion testing prior to new system installation. These tests determine how much or how many coats of a specific primer are required to function properly based upon tested field conditions.
When in doubt as to a particular substrate or project specific application, contact RMI Technical Services.