Uses A thermal insulation and base for most membranes over any structural deck. A protective layer over soft insulations susceptible to traffic damage. When FMRC and/or UL approved systems are specified. Can be used as an overlay board over foam plastic roof insulation, as recommended by NRCA Bulletin No. 9. In all applications, use of Perlite insulation must be approved by the specific roof membrane manufacturers.  Return to Perlite Roof Insulation