Built-Up roofs or BURs have been in use for over a century. Commonly referred to as “tar and gravel” roofs, BURs were first introduced as “composition roofing” in the 1840’s and are typically used on low-slope buildings. BUR systems are generally composed of alternating layers of bitumen and reinforcing fabrics that create a finished membrane:
- Bitumen can either be asphalt (refined from crude oil), coal tar (derived from distilled coal), or cold-applied adhesives (solvent-based asphalts). Asphalt and coal tar are heated first and applied by mop or mechanical spreader. Cold-applied adhesives, on the other hand, can be applied without heat and can be sprayed on, or applied using a squeegee. Since it doesn’t emit toxic fumes, it is the better choice for environmentally sensitive projects.
- Reinforcing fabrics are also known as roofing felts or ply sheets. Roofing felts are reinforced with either glass fiber mats or organic mats. Both bitumen and reinforcing fabrics are alternately layered before a layer of surfacing material is applied.
- Surfacing material is then applied to cover the entire surface. Gravel, slag or mineral granules are commonly used as surfacing material, and is readily available to any San Diego, CA, roofing contractor. Virtually any similar material can be used depending on availability. Other materials such as fasteners, caulking material and roof insulation are also used to complete the installation.
While not exactly a first choice for residential roofing in San Diego, BURs are still favored by building owners and operators for its benefits over other types of roofing:
- It’s waterproof and can withstand extreme weather. Modern formulations of bitumen have made it resistant to water damage and normal wear and tear.
- It’s low maintenance.
- It has superb tensile strength (i.e. it doesn’t break under extreme stress) and can withstand high roof traffic.
If you’re looking into getting BUR (or any other type of roofing) for your building, choose RSI Roofing & Solar. As a trusted San Diego roofing company, you can count on us for roofing products and services of the highest quality. We even offer 24-hour emergency roofing services to ensure that any problems with your roof can be fixed immediately.
Give us a call at (858) 278-7200 or fill out our contact form to get started.