Modified Bitumen systems consist of asphalt with modifiers added to give it durability. These are either one- two- (most common), or three ply-systems. They are factory manufactured and combine the redundancy of built up roofing with the ease of application of a single-ply system.
Modified Bitumen Systems are of two kinds:
- SBS (Styrene Butadiene Styrene) systems are usually installed with hot asphalts or cold adhesives.
- APP (Atactic Polypropylene) systems in almost every case are installed using the torch method.
Both SBS and APP systems can be reinforced either with glass or with polyester. Among the advantages these systems offer:
- The rolls of these roofing materials are factory-manufactured, ensuring quality control.
- These systems are well-suited to expand or contract with the movement of the building they protect.
- The modified bitumen roof systems can be finished with a variety of surfaces that enhance their resistance to oxidation and damage from UV rays.