A glass-fiber reinforced polyisocyanurate foam core with solid aluminum foil facers on both sides. Can be installed exposed to the interior without thermal barrier. Other thicknesses available.
Building Code Compliance Complies with ASTM C 1289 Type I, Class 2. Meets IBC/IRC requirements for foam plastic insulation. See SBCCI PST & ESI ER 9574C, BOCA-ES RR 98 25, ICBO-ES ER 3223. FM 4880 - see Factory Mutual Approval Guide.