DERBIBOARD is a high performance polyisocyanurate insulation board designed to provide a clean, strong base for a variety of roofing systems. The polyiso foam has superior fire resistance as well as the ability to retain high R-values. The foam core is integrally bonded to non-asphaltic fiber-reinforced organic felt facers for added strength and dimensional stability. A tapered system is also available; designed to provide a positive slope to roof drains. Product comes in a variety of thicknesses with a wide range of R-values.