Johns Manville AP Foil-Faced Polyiso Continuous Insulation board consists of a uniform closed-cell polyisocyanurate foam core bonded on each side to a foil facer. One side has a reflective foil facer and the other side has a white non-reflective foil facer to suit your building needs. Polyiso provides one of the highest R-values per inch of any rigid insulation (R-6.0 at 1 inch). Furthermore, when properly installed, AP Foil-Faced Polyiso Continuous Insulation functions as a water-resistive barrier, vapor barrier and air barrier, eliminating the need to install additional components. AP Foil-Faced Polyiso Continuous Insulation provides exceptional heat, moisture and air control to protect your building’s exterior wall assembly.