CertainTeed's FlintBoard® ISO CV is a high-performance insulation product designed for use in steep-slope, slopes 3:12 or greater, roofing applications where the existing roof does not have sufficient air circulation, as required by most roof shingle and metal roof manufacturers. FlintBoard® ISO CV allows heat to cross vent and dissipate while providing a nailable surface and efficient insulation in a one-step process. Common uses of FlintBoard® CV include cathedral and vaulted ceilings or exposed ceilings. FlintBoard® ISO CV is a venting composite insulation board that consists of a 4′ X 8′ panel of closed cell rigid polyisocyanurate (ISO), a layer of solid wood spacers, creating a standard 1″ cross venting air space and a top layer of APA/TECO rated OSB or plywood. It's rigid insulation board offers the highest R-value (resistance to heat flow) per inch available and long-term thermal resistance values (LTTR*) from 5.7 to 27, LTTR. FlintBoard® CV is made to order in...See More 4' x 8' (1220 mm x 2440 mm) size panels and in nominal thicknesses from 2.5" to 6.5". Reach out to your local CertainTeed Territory Manager to request a sample and demonstration of FlintBoard® ISO CV. *LTTR is the industry standard method for calculating the 15-year time-weighted average for roof insulation. See Less