Built-Up Membrane Roofing Systems (BUR) are actually as simple as they sound. They’re fabricated with layers of bitumen with alternating plies of reinforced felts. The simplistic layer design gives this unique membrane outstanding water and weathering resistance. According to the National Roofing Contractors Association, BUR Membranes have been used in the U.S. roofing industry for more than 100 years. Generally known as “tar and gravel” roofs, BUR membranes have been a time-tested and trusted choice for simple flat-roofing. BUR Systems have an advantage over other flat roofing systems: they can be hot applied or cold applied. This flexibility relieves some of the limitations of common roof installation, making it easier for roofers to install without compromising time schedules or your company’s business.