RUBEROID® Torch Granule Membrane is a tough, resilient modified bitumen membrane manufactured to stringent GAF specifications. Its core is a strong, resilient, non-woven polyester mat that is coated with weather resistant APP polymer modified asphalt. Its core is a strong, resilient non-woven polyester mat that is coated with weather-resistant, APP polymer-modified asphalt. The membrane is available with a smooth surface.