Built-Up Roofing

Built-Up roofing, also referred to as BUR, is a common type of roof material. BUR is used for low-slope or flat roofs. Several layers of roof material such as tar paper and asphalt (bitumen) are installed in a sequence of layers that adheres to the roof deck or base. Hence, the name of BUR or Built-Up Roofing. The top-most layer usually consists of aggregate material such as fine stone or gravel. Using a BUR system creates a continuously sealed surface. In contrast, regular roof shingles are not sealed. Therefore, shingles are applied to a pitched roof system so that rain water flows off of the roof’s surface.

Water does not flow off of a flat roof and a flat roof must be properly sealed. Flat roofs hold the weight of snow and ice which is a drawback of this type of roof. When sun rays melt the snow and ice, only then, does water flow away. Any type of roof material requires occasional maintenance to keep it in stable condition. Four-ply roofs, another type of BUR, involves a series of layers of tar and fine gravel. By using alternating layers of asphalt and roof fabric, the layers build up and adhere to the roof surface. ​.