Modified Bitumen Roofing often just referred to as ‘modified roofing’ is a premium, low-slope commercial option.
This type of low slope roofing material is referred to as modified bitumen due to its material makeup which consists of modifiers that 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. A standard SBS modified bitumen roof system is a two-ply system applied in rolls that overlap the edge of the previous roll. SBS systems are usually installed using hot asphalts or cold adhesives. The other type of modified bitumen roof is the APP (attactic polypropylene) which is used for its ability to increase the aging ability of the roof system. APP systems are usually installed using the torch method. SBS is often the more popular system as the synthetic rubber additive increases the products flexibility.
Both SBS and APP systems can be reinforced with either glass or polyester. There are a variety of advantages with these types of systems, such as the rolls of material being factory manufactured which ensures quality control. These systems are also well-suited to expand or contract with the movement of the building they protect.
A modified bitumen roof system is versatile and can be finished with a variety of surfaces that enhance their resistance to oxidation and damage from UV rays.