Built Up Roofing (BUR)
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Built-up roofing, often called BUR or simply a tar-and-gravel roof, is one of the oldest and most proven flat roofing systems in commercial construction. It is created on site by alternating layers of bitumen and reinforcing fabric, then finishing the surface with gravel or a reflective coating. Decades of use on warehouses, schools, hospitals, and government buildings have made BUR a known quantity for property owners who want a thick, redundant, dependable roof. Weather installs and maintains built-up roofing and can help you decide whether it is the right system for your flat or low-slope building.
How Built-Up Roofing Works
A built-up roof is assembled in layers, or plies, directly on the roof deck. It typically begins with insulation and a base sheet, followed by alternating layers of hot or cold-applied bitumen and reinforcing felt or fiberglass mat. The number of plies can be adjusted to the needs of the building, with more plies adding thickness, durability, and redundancy.
The final layer is a surfacing material, most often a flood coat of bitumen embedded with gravel or mineral aggregate, though reflective coatings are also common. The gravel protects the membrane from UV damage and foot traffic, while the multiple plies beneath ensure that a single point of damage does not compromise the whole roof. This layered, monolithic construction is what gives BUR its long-standing reputation.
The Perks Of A Built-Up Roof
Built-up roofing offers excellent waterproofing thanks to its multiple redundant layers, and the gravel or aggregate surface provides strong protection against UV rays, fire, and physical wear. With proper maintenance, a BUR system commonly lasts 20 to 30 years.
These roofs also provide good insulation value, help with sound dampening, and require relatively low maintenance once installed. Because BUR is a familiar system, repairs are straightforward and most roofing professionals can service it. Contact Weather today for a price quote on built-up roofing and to learn whether it fits your commercial property and budget.
Built-Up (BUR) FAQs
What is built-up roofing?
Built-up roofing, or BUR, is a flat roof system made by layering bitumen and reinforcing fabric on the roof deck, then finishing the surface with gravel or a reflective coating. The redundant layers create a durable, waterproof membrane.
How long does a built-up roof last?
With professional installation by Weather and regular maintenance, a built-up roof typically lasts 20 to 30 years. Routine inspections help catch small issues before they become costly.
Why is it called a tar-and-gravel roof?
Built-up roofing earned the nickname because the system traditionally uses asphalt or coal-tar bitumen topped with a layer of gravel. The gravel protects the membrane from UV exposure and foot traffic.
Is built-up roofing good for flat roofs?
Yes. BUR is designed specifically for flat and low-slope commercial roofs, and its multi-ply construction makes it well suited to large, level surfaces.
How many layers does a built-up roof have?
The number of plies varies by building, but most BUR systems use three to five layers of bitumen and reinforcing felt. More plies add thickness, durability, and redundancy.
Can a built-up roof be repaired?
Yes. BUR is a well-understood system, so damaged areas can typically be patched and re-surfaced without replacing the entire roof. Weather can assess and repair localized damage.
Is built-up roofing energy-efficient?
It can be. A reflective coating or light-colored aggregate surface reduces heat absorption, and the thick layered construction adds insulation value that helps regulate indoor temperatures.
What maintenance does a built-up roof need?
Regular inspections, keeping drains and the surface clear of debris, and checking flashing and seams after storms are the main maintenance tasks. Weather can set up a maintenance plan for your property.
Will Weather help with insurance claims for built-up roofing?
Yes. Weather can work directly with your insurance provider to simplify the claims process and speed approvals for repair or replacement of a built-up roof.