Torch down Roofing required an open-flame propane torch. In this installation method, sheets of modified fiber-reinforced roll roofing is rolled out on to roof and a roofing professional uses a hand-held propane torch to heat the material and adhere it to the surface. Once the layers reach the right temperature, seams are melted together to create a waterproof seal. This type of roofing can expand and contract without melting or cracking. It has a high tolerance for both heat and the cold that it with experience during seasons.