Roofs made of APP (atactic polypropylene) or SBS (styrene butadiene styrene modified bitumen have been around since the early 1970s and make up a sizeable percentage of commercial roofing installations. Modified bitumen roofing is an updated version of a much older technology, the traditional built-up roof. Like built-up roofs, modified bitumen roofs are composed of layers of roof felt covered with asphalt, next they are topped with a ceramic granulated cap sheet instead of gravel or stone set in asphalt. A wide range of options allow the roof to be adapted to best suit the individual building.


  • Durable, weather resistant, and flexible
  • Strong protection against leaks and wind with a single sealed surface
  • More lightweight and economical than built-up roofs
  • Energy Star compliant with eligibility for LEED credits
  • Multiple options for color and customization
  • Easily repaired


Modified bitumen has both base and cap sheets that have several application methods such as:   mechanically fastened, hot asphalt, cold asphalt, torch applied and self adhered.