Built-Up Roofing (BUR) Tar And Gravel Systems
admin | October 9, 2025 | | No Comments

Built-up roofing, commonly called BUR or tar and gravel roofing, has protected commercial and industrial buildings for over a century. This time-tested system remains popular today because of its durability, affordability, and proven track record. Any experienced roofing contractor will tell you that when properly installed and maintained, a BUR system can last 20 to 30 years or more, making it an excellent investment for flat and low-slope roofs.

What is Built-Up Roofing?

Built-up roofing consists of multiple layers of roofing felt or fiberglass mats bonded together with hot asphalt or coal tar pitch. The process involves alternating layers of bitumen (tar) and reinforcing fabrics, typically creating three to five plies. Finally, the system is topped with a protective layer of gravel or mineral granules that shields the tar from UV damage and provides fire resistance.

How BUR Systems are Installed

Installation begins with preparing the roof deck and ensuring it's clean, dry, and structurally sound. Workers then apply a base sheet, which is the first layer of reinforcement attached directly to the deck.

Next comes the layering process. Hot bitumen is mopped onto the base sheet, and a ply sheet is rolled into the hot tar. This process repeats for each additional layer, with each ply overlapping the previous one. The number of layers depends on your building's needs and local climate conditions.

Finally, a flood coat of hot bitumen is applied across the entire roof surface, followed immediately by spreading gravel or stone.

Advantages of Tar and Gravel Roofing

• Durability: The multiple layers create a thick, robust membrane that resists tears and punctures better than single-ply systems. This makes BUR ideal for roofs with foot traffic or mechanical equipment.
• Fire Resistance: The gravel layer provides excellent fire protection, which is why many building codes prefer BUR systems for commercial structures. The stone won't burn and helps prevent fire spread.
• UV Protection: Unlike exposed membrane systems, the gravel shields the waterproofing layers from harmful sun rays. This protection significantly extends your roof's lifespan.
• Cost-Effective: BUR systems typically cost less than many modern single-ply membranes, and their long lifespan means better value over time.
• Weatherproof: The multiple layers create redundancy in waterproofing. If one layer develops a small breach, other layers continue protecting your building.

Considerations and Limitations

BUR systems are heavy, requiring strong structural support. Make sure your building can handle the weight before installation.

The installation process involves hot tar, which creates strong odors and requires experienced professionals for safe application. This isn't a DIY project.

Locating leaks can be challenging because water can travel between layers before appearing inside your building.

Is BUR Right for Your Building?

Built-up roofing systems offer proven performance and excellent value for commercial and industrial flat roofs. Contact a qualified roofing contractor at 70 Sunrise Highway #500 Valley Stream, New York 11581 (516)- 252-3001 https://www.gafroofinglongisland.com right away for a professional assessment and free estimate tailored to your building's specific needs.