Torch-on roofing is arguably the best solution for roofs with less than 4″ horizontal in 12″ vertical slope. It is typically installed as a two-ply heated welded system to an asphalt impregnated overlay board which has been fastened to the substrate. Torch-on is the next generation of “tar and gravel” roofing, which has actually been hot asphalt and pea gravel since around 1960. It works on the same principle: layers of fibreglass or polyester reinforcement embedded in asphalt and welded together, topped with a protective aggregate surface. The only differences are in the application, and that some alterations have been made to the composition of the asphalt. Torch-on roofing is a much more aesthetically appealing product than its predecessor and is available in almost every color of the rainbow. In addition, the installation process is much less labor intensive. Because the application requires more finesse, care and attention, applicators tend to be much more diligent in monitoring quality. However, skillful torch-on roofing requires extensive experience and training. Selection of a torch-on roofer must be done with the utmost care. As the material itself doesn’t come cheap, leak investigations and repairs can become very costly. In addition, always ensure the torch-on roofer has liability insurance with a hot work endorsement. Roofing fires can be tragic.
E.P.D.M. or ethylene propylene diene monomer is typically referred to as “rubber” roofing. The single-ply sheet is available in 1.1 mm or 1.5 mm thicknesses and comes in roll sizes of up to 50′ by 250′.
T.P.O. Roofing or thermoplastic polyolefin is the next generation of single ply roofing. The costs associated are in the middle between torch-on and rubber, closer to rubber. Again, TPO is available in sizes up to 50′ by 250′ and offers slightly more durability than E.P.D.M.