Among the many types of roofing systems available is the built-up roofing system (BUR), usually applied to “flat” or low slope roofs. The traditional flat-roof system used for more than 100 years, also is known as a “mop-on” or “tar and gravel” system.
Benefits of Conventional and Built-Up Roofing include multiple layered protection, thermal and UV performance, fire and up-lift stability, strong tensile strength and durability for high roof traffic and multiple climate conditions.
The built-up roof system provides waterproofing through a combination of multiple layers of roofing felt, tar and gravel.
These hot systems involve the installation of felt in three-feet rolls sealed with heated rubber enhanced asphalt or coal tar, and surfaced with a coverage of gravel aggregate cast into the molten asphalt or coal tar.
Walls, curbs and roof penetrations are sealed separately with flashing felts also set into the hot asphalt or adhesive.
These roof types have exceptional traffic durability and protection from ultraviolet rays from the sun, coal tar and rubber enhanced asphalt have exceptional durability to pooling water.
Durability and Maintenance
The conventional built up roof provides superior durability in areas of corrosive conditions, such as around cooling towers, exhaust vents in manufacturing applications and high traffic areas.
Areas of reduced drainage or pooling water are acceptable when addressed with coal tar or rubber enhanced asphalt. These roofs provide superior integrity in areas of temperature fluctuation, wind conditions and solar radiation.
Depending on the number of layers and the products used, low slope built up roofing can be effective for up to 30 years.