Built-Up Roofing Systems have good waterproofing characteristics but suffers from a loss of ductility after prolonged exposure to UV.

Common Issues


Roof Ponding – Water retention on a low-slope roof caused by inadequate roof drainage or structural deflection.	Alligatoring – Cracking of a built up roof producing a pattern similar to an alligator’s hide.	Weathering – Deterioration of a built up roof caused by exposure to weather, thermal expansion, acid rain and UV degradation.	Extreme Heat – Excessive heat build up on dark colored roofs. Temperatures can reach 180°F or more in the summer.

Built Up Roofing

Asphalt degradation is a growing concern. UV-rays oxidize the surface of the asphalt built up roof and produces a chalk-like residue. As plasticizers leach out of the asphalt, the asphalt built up roof becomes brittle. Cracking and alligatoring inevitably follows, allowing water to penetrate the system causing blisters, cracks and leaks.

Perform annual inspection and repair any damage immediately. Penetrations like vents, pipes or ductwork can open up and may need to be re-sealed periodically. Blisters or delaminations should be cut off and repaired since they will leak over time.

Leaks in built up roofs are difficult to isolate and a seamless roof coating system is the best alternative to roof replacement.

Learn more about Built Up Roof Repair or Built Up Roof Coating.

Ballasted Built Up Roofs / Tar and Gravel

Gravel removal (spudding) is required. We recommend installing at least 2” thick sprayed polyurethane foam on the roof to smooth out the dimples and create positive slope towards the drain. EnergyGuard® Acrylic Elastomeric Coating or EnergyGuard® Silicone Elastomeric Coating should be applied over the new foam to prevent UV degradation.

Built Up Roof Coating & Restoration

Add 10 or more years to your built up roof with our built up roof restoration system. Get a seamless roof without costly tear off and disruption. Stop roof leaks and prevent further degradation.

EnergyGuard® Acrylic Elastomeric Coating is a good choice if your smooth built up roof is properly sloped and does not pond water.
EnergyGuard® Butyl Elastomeric Coating is excellent for smooth built up roofs with minor ponding that cannot be rectified. Larger ponds should be corrected or area drains need to be installed.

Tags: Acrylic Coatings, Air Conditioning, Butyl Coatings, Elastomeric Coatings, Flat Roofs, Roof Coatings, Roof Restoration, Solar Reflectance

What’s a Built Up Roof?

A built-up roof or BUR is a class of low-slope roof that consist of layers of reinforcing felt between either asphalt or coal tar bitumen.

A lot of old buildings with low slope or flat roofs are topped with built-up roofing made from layers of asphalt-coated roofing felt. The top layer is usually covered with rock or gravel, which serves as a ballast to hold the roofing material down and protect it from UV damage. Built-Up Roofs with gravel surfacing are also known as Tar and Gravel roofs. Typical lifespan of a built-up roof is 10 to 20 years depending on weather conditions.

Types of Built Up Roofs

Built-Up Asphalt Roofing
Ballasted Built-Up Roofing
Cold Applied Built-Up Roofing
Built-Up Coal Tar Roofing
Tar and Gravel
Glass-Fiber-Reinforced Asphalt Emulsion Roofing

Solar Reflectivity of BUR

The solar reflectivity of BURs depends on the color of the surface layer. Four BUR surfacing options are aggregate, smooth, mineral cap, and protective coating.

Black asphalt roofs can reach 180°F or more in the summer. High temperatures and UV-rays accelerate asphalt degradation. The heat load of a black roof can severely degrade the performance of rooftop air conditioning equipment. To make matters worse, the heat build up raises plenum temperatures thereby increasing cooling costs in the building.

Elastomeric coatings provide the highest reflectivity and is a very popular option for building owners. White roof coatings can reflect up to 90% of the heat from the sun.