Built-up-roofing (“tar and gravel” roofing) designates common roofing materials used on low slope (flat) roofs. The acronym BUR is not new, but has been used in the US for more than a century.
Such a roof system is composed of bitumen and reinforcing fabrics (ply sheets or roofing felts), applied in layers. The result is a finished protective membrane applied on a mechanically fastened base sheet. This technology is efficient and fully adhesive to roof decks. Reinforcing fabrics contain organic mats or glass-fiber mats.
Built-up roof systems are surfaced using mainly hot asphalt, aggregate (slag, mineral granules, gravel), aluminum coatings, elastomeric coatings or glass-fiber. The drainage system is another important element of a built-up roof, for collecting water to the sewer and fast evacuation in case of torrential rain.
According to a credible Fort Worth roofing contractor, a BUR system has many pros. First, it is reliable – as state most roofing contractors. There are such roofs installed 50 years ago that are still standing strong. Besides, the multi layers of saturated felts and bitumen create a resistant barrier against the elements.
A BUR system also provides good energy-efficiency if it is coated with special materials designed to maintain a constant building temperature throughout the seasons.