“Torch down” is the most commonly used type of roofing for flat or very slight pitch roofs. The official name is “modified bitumen” (pronounced buy-TOO-men). It is a rolled roofing product that consists of a tough membrane, embedded in a thick layer of asphalt. Rubbery additives with high quality resins in the asphalt allow the roofing to expand and contract, where other roofing systems just crack. The roofing can bond tightly to metal flashings and move with them, while maintaining the bond. This flexibility is the main benefit of modified bitumen and is a big factor in its’ success.
Torch down roofing is completely impermeable to rainwater and is also resistant to otherwise damaging UV rays. It won’t melt or gather large puddles of rainwater, so it is already weatherproof to a good extent. Torchdown roofing is extremely durable. The combination of asphalt and resin means that it is resistant to punctures and other abrasive damage. The strength and resistance of torchdown roofing means that it not only has a life of up to 20 years, but that it will also be virtually free of repairs; except in the most extreme circumstances.