Rigid NGX Foam Insulation · 4x8-1-1/2" · R-7.5Rmax Thermasheath-3 is an energy-efficient thermal insulation board composed of an environmentally sound closed-cell polyisocyanurate foam core bonded to reinforced aluminum foil facers on each side. It is suitable for use in walls, ceilings and some limited roofing applications in new construction and in thermal retrofit construction within existing buildings. It is ENERGY STAR approved, and an ideal choice for cavity walls, masonry walls, vaulted ceilings and many other building envelope continuous insulation applications. It is an energy-efficient thermal insulation board designed to meet the many demands of today’s building industry. This insulation is suitable for use in walls, ceilings and some limited roof applications in new construction for commercial, residential, agricultural and industrial buildings and in thermal retrofit construction within existing buildings.