Atlas foam roof insulation is well established in the building materials industry through its ACFoam® family of insulation products. Cores of these products are polyisocyanurate (polyiso) foam, the most widely used and accepted rigid roof insulation in use today. It is estimated that 60-65% of all commercial new or re-roofing applications nationwide use polyiso. Rigid polyiso is a safe, cost-effective, sustainable and energy efficient construction material. All of Atlas nailable polyiso insulation is QualityMark certified, giving consumers an easy way to identify quality products that meet or exceed listed LTTR-values. All products in our ACFoam® Polyiso Roof Insulation line are closed-cell, rigid foam board, flat or tapered insulation. Polyiso is the only foam plastic roof insulation that can be used without the need for a thermal barrier.