Built-up roofing, commonly referenced as BUR, is one of the oldest systems in use. Built-up roofing is installed by laying multiple layers of roofing felt into hot asphalt. BUR provides more protection from the elements and also from traffic on the roof than other types of roofing. It is the most durable system Twin City Roofing installs.
Built-up roofing is commonly installed with gravel surfacing, which helps it to withstand considerable hail with little damage. The gravel also provides protection from the effects of UV radiation. BUR can also be installed without the gravel when the roofing felts are coated either with another layer of asphalt or a variety of coatings that are available.
Another type of built-up roofing is referred to as modified bitumen. This material is made with a modifier added in the manufacturing process, which gives it more flexibility than regular roofing felts. It is a heavier weight material than the fiberglass felts. It is available either with a granular surfacing or can be smooth surfaced with coatings being applied after installation.