Owens Corning Foamular® Tapered Roofing Products Extruded Polystyrene (XPS) Rigid Foam Insulation provide performance & value in low slope roofing systems and are designed to be used over structural roof decks. Thermapink® tapered roof insulation provides a thermally efficient, moisture-resistant positive drainage slope for use under single-ply or other types of roofing systems.