What Does a Built-up Roof Mean?

Updated: Aug 17, 2020

For low sloped roofs, Los Angeles roofers tend to recommend a built-up roofing system. This multi-ply roofing installation involves several coated sheets of asphalt that are applied to a standard roofing base with adhesives.

While built-up roofs or BURs are cited for their superior durability, this roofing systems susceptibility to collect debris makes maintenance a required cost. While roof inspections are generally recommended on a five year calendar for traditional asphalt shingle systems, in areas like Los Angeles and Orange county, regular inspections are required to keep a built-up system properly maintained.

Naturally the concept used in built up roofing has existed for hundreds of years, but the major advancements in built-up roofing technology in the 20th century has been improved insulation for a higher level of energy efficiency. If one were to deconstruct a built-up roofing system they would find three key components. Bitumen material, a surfacing material, and an asphalt ply system. The bitumen material used in BUR systems can either come in a hot (liquid) or a cold (solid) form depending on the particular system.

The most common material used for a surfacing material is traditional gravel. The gravel helps finish the roof and it’s weight helps keep the Built-up roof installation in place. A major obstacle in pricing built-up roofing systems is estimating the cost of the gravel and other surfacing materials as these vary based on region, weather, and local city ordinances. Built up roofing. A recent study of the Los Angeles roofing sector found that over 32% of commercial roofing jobs involved built up roofing systems. While in some regions metal aluminum roofs are the industry standard, built up roofing systems have an appeal with Los Angeles roofers due to their increased resistance to sea salt damage especially for low sloped roofs.

The main industry terms for the various forms of built up roofing systems are cold, hot, and asphalt builds. As of 2020, ballistic asphalt is the most popular type of BUR system on the market. Customers with environmental concerns generally avoid the toxic hazards associated with asphalt BUR systems in favor of cleaner cold systems. The main drawback of going with a cold installation is the increased cost and labor time compared to other built up roofing systems.

  • Great Value: When the quality of tile BUR is balanced to its quality and quick installation time, built up roofing systems add tremendous value to property owners.

  • Long-Term Weathering: Excellent long-term heat and weather resistant.

  • Inherently Flexible: No need for plasticizers.

  • Heavily standardized process: BUR systems are an industry standard for Los Angeles roofers and have a heavily standardized installation process.

  • Versatile Application Methods: Including high-performance roofs requiring high wind uplift, increased puncture resistance, or quick economical systems.


  • Cost: BUT roofing systems generally fall between its two main competitors being more expensive than Asphalt shingles and less expensive than Slate. As a lightweight yet sturdy material, asphalt plye is easy and inexpensive to install. It's also easy to clean with a power washer, keeping down the cost of maintenance.

  • Durability:BUT roofs resists punctures and is flexible enough to stretch as the structure settles, as well as withstanding a wide range of thermal expansion and contraction.

  • Efficiency: BUT roofing systems are reflective enough to reduce cooling costs during hot weather. High-quality products are Energy Star-rated for energy efficiency.

  • Environmental Impact: The installation process for BUT roofing is seen as one of the most eco friendly in the Los Angeles roofing industry.


  • Quality: There is a large variance in quality between products and types BUT roofing installations

  • Longevity: As an industry standard, BUT roofings main drawback is its inclination for wind damage, making BUT unpopular for coastal areas like Los Angeles and Orange County

  • Leaks: When a BUT roof does leak, the leak can be hard to find and even harder to repair. Repairs that require removal of part of the roof covering can be expensive.

  • Deterioration: Despite high quality material BUT roofing systems can deteriorate under high thermal and solar loading and may not last as long as expected in hot Los Angeles summers.

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