A method combining layers of bitumen surfaces and roofing fabrics that build up your roof, creating a durable waterproof membrane.
Built-Up Roofing methods combine layers of bitumen surfaces and roofing fabrics that build (or ply) up your roof to create a durable waterproof membrane. This flat roofing technique has been utilized in the US for over 100 years and is also formerly known as a tar and gravel roofing system.
How is a BUR system installed?
Alternating plys are composed of bitumen and reinforced fabric, creating a membrane.
Bitumen used in roofing systems typically derives from a cold-applied adhesive, OR coal tar or asphalt, which are heated before application.
After the membrane is applied and sealed, an aggregate is applied evenly over the entire surface of the roof which, depending on the protection required from weather, includes gravel or rocks, mineral or fiberglass cap sheets, a hot asphalt pour, or elastomeric or aluminum coatings.
Each layer builds up the roof, contributing to a reliable roofing system that can be expected to last 40 years if properly installed and maintained. Some industry studies show built-up roofing systems have the shortest life expectancy of all commercial roofing options with the shortest spans reported to be between 15-20 years, so maintenance expectations should be considered when evaluating built-up roofing systems.