Commercial Roofing

Modified Bitumen Roofing

Modified bitumen asphalt roofs

Modified Bitumen roofing systems are a durable, weather resistant type of low slope roof.

Common Types
  • SBS
  • APP
Common Applications
  • Conventional
  • Inverted
Manufacturing Method

Modifiers are added to standard roofing asphalt to replace plasticizers removed during the distillation process. Bitumen is reinforced with fiberglass or polyester fiber matting in order to increase durability and strength.

The two most common types are SBS and APP. The use of SBS (styrene-butadiene-styrene) increases the flexibility of the membrane and allows it to have stronger expansion and contraction capabilities. APP (attactic polypropylene) increases the aging ability of the roof system. SBS is often the more popular system as the synthetic rubber additive increases the products flexibility.

Application Method

Modified bitumen roof systems can be installed with the common torch method, asphalts, or cold adhesives. A standard SBS modified bitumen roof system is a two-ply system applied in rolls that overlap the edge of the previous roll.

  • Very durable
  • Weather resistant
  • Easy to repair
  • Factory manufactured rolls are easier to install and ensure quality control
  • Flexible, expands and contracts

Godfrey Roofing Inc can repair or install modified bitumen roofs for clients in the Greater Ottawa region – please view the commercial roofing services section for more details.