Built-up roof membranes, also referred to as BUR, have been in use in the U.S. for more than 100 years. Built-up roof systems, which are much less common today compared to 50 years ago, are commonly referred to as “tar and gravel” or “asphalt and gravel” roofs. BUR systems generally are composed of alternating layers of bitumen and reinforcing fabrics that create a finished membrane. Due to increased demand for sustainable roofing products, noxious odors associated with the products and the labor-intensive nature of built-up roofs, the method has largely been replaced with single-ply roof systems. Yet, many built-up roofs still exist today, and will continue to for years to come.
- Fully adhered with hot bitumen or cold adhesive
- Multiple plies
- Smooth or flood and gravel are available for surfacing