Mod Bit
Modified bitumen roofs, or “mod bit” roofs, consist of rolls of reinforced asphalt where the asphalt has been modified to possess plastic or rubber-like properties. The two most commonly used types of modifiers are Atactic Polypropylene (APP) and Styrene Butadiene Styrene (SBS).
According to the National Roofing Contractors Association: “Polymer-modified roof membranes are composed of reinforcing fabrics, usually polyester, glass-fiber, or both, that serve as the carriers for the hot-poly-modified bitumen as it is manufactured into roll material. The purposes for reinforcements in polymer-modified bitumen sheets essentially are the same as felts in a built-roof membrane. The reinforcements help to keep bitumen in place within the sheet, provide tensile strength and allow for varying degrees of sheet elongation. …In the manufacturing process, the reinforced membranes are saturated, impregnated, or filled and coated with polymer-modified bitumen. The end result is a relatively strong, heavyweight roof membrane material.”
Donan Engineering’s team of professional engineers has the knowledge and experience to successfully study all types of Modified Bitumen roof systems, whether the problem is a product of installation, material defect, storm damage, or any other potential cause of loss.