Asphalt based roof systems have a long track record of excellent performance. Unlike single-ply roof systems, an asphalt system uses multiple layers of asphalt, held together with felts or modified materials to create a thick, durable waterproofing membrane. These multiple layers make asphalt systems high resistant to punctures. Asphalt systems also have many surfacing options that can increase solar reflectivity and increase the life span of the roof. Surface options widely available today include coatings, gravel and granular surfaced cap sheets.