Modified Bitumen and Built-Up Roofs

Modified Bitumen

roof-1Composed of asphalt and reinforced with either polyester or fiberglass, modified bitumen roofs are a blend of traditional and modern roofing technologies. Two different polymers, Styrene Butadiene Styrene (SBS) or Atactic Polypropylene (APP), are used to modify the membrane and impart greater elasticity and temperature flexibility. Since polyester fiberglass fortify the roof system, it exhibits more strength and resistance to punctures and is typically installed in various layers to provide a multi-tier protection system from water, extreme temperatures and wind uplift.

Modified Bitumen Roof Systems do differ in how they are installed on the roof based on the polymer sheet chosen. SBS, a polymer that gives bitumen characteristics similar to rubber, is typically installed with hot asphalt or cold adhesives. APP, a thermoplastic polymer, is almost always installed utilizing the torch method. SMART Roofing’s team of professionals will assess your roof and suggest the best application approach for your facility.

Roofer preparing part of bitumen roofing felt roll for melting by gas heater torch flame

Roofer preparing part of bitumen roofing felt roll for melting by gas heater torch flame

Built-Up Roof (BUR)

Built-Up Roof systems consist of multiple layers of felts, fabrics or mats that are saturated with bitumen, either asphalt or coal tar pitch. The surface of the roof can have a gravel application, a mineral cap sheet or a weather resistant coating to help protect the bitumen and felts from premature weathering.

BUR is one of the oldest low-slope roof systems that are still applied to commercial roofs today. BUR's 120 year track record is unsurpassed in the roofing industry and continues to offer building owners dependable service.

ReNew Home Designs has thousands of square feet of installation experience with these types of roof systems. A SMART Roofing representative can review the performance characteristics associated with the various Modified Bitumen and Built-Up Roof systems so the right roof system can be selected based upon the conditions associated with your individual building.