These roofing techniques are installed in sheets that overlap each other, and the area that overlaps is then heated with a torch so they bond together.
The materials used in most torch down roofing applications are also known as rubberized asphalt. The melting of this overlapping bitumen by torching them together creates a very durable and highly resistant roof, which gives most torch down roofs an average lifespan of around 20 years.
The reason a large number of flat roofs are done with torch down roofing materials has to do with rubberized technologies that make them highly beneficial for flat roofs that might collect water in some spots. Older buildings might have drainage problems that cause small puddles to form, but with rubberized torch down roofing materials these puddles will dry in the exterior of the building, rather than drain through to the interior. Though this highly water-resistant material might cost a little more than some other methods, it is still regarded as the best type of roofing material for flat roofs that might not drain as rapidly as other types of commercial roofs.
Another great benefit to torch down roofing materials is their ease of installation. There are no noxious fumes and other environmental hazards that the installer has to contend with. The torching process only releases a small amount of odor when the torch heats the surface, causing the two layers to bond together.