Built-Up Roofing (BUR)
The original flat roof system, refined over a century. Built-up roofing layers multiple plies of asphalt and reinforcing fabric to create one of the most durable and waterproof commercial roof systems available.
A Century of Proven Performance
Built-up roofing is the grandfather of commercial flat roofing — and it’s still going strong. For over 100 years, BUR systems have protected warehouses, retail centers, and commercial buildings. The multi-layered approach to waterproofing remains one of the most reliable systems available.
How Multi-Ply Protection Works
A BUR system is built in layers, alternating between hot asphalt and sheets of reinforcing fabric (typically fiberglass). Each layer adds waterproofing and structural integrity. The result is a monolithic membrane that’s highly resistant to punctures, tears, and water intrusion.
Gravel: Function Over Form
The gravel surface on a traditional BUR roof isn’t just aesthetic — it serves three critical functions. It protects the asphalt from UV degradation, provides ballast against wind uplift, and adds a significant fire resistance rating to the assembly.
Modern Improvements
Today’s BUR systems benefit from decades of material science improvements. Fiberglass reinforcing has replaced organic felts, cold-applied adhesives offer an alternative to hot asphalt, and reflective coatings can be applied to meet modern energy codes. The fundamental technology is proven — the materials just keep getting better.
How We Install Built-Up Roofing (BUR)
Deck Inspection
The existing roof deck is inspected for structural integrity. Any wet insulation or damaged decking is identified and replaced.
Insulation & Vapor Barrier
Rigid insulation boards are installed over a vapor barrier to achieve the required R-value and create positive drainage.
Ply Application
Alternating layers of hot asphalt and reinforcing felt or fiberglass fabric are built up to create a 3-4 ply waterproof membrane.
Surface Protection
A flood coat of asphalt topped with gravel, mineral cap sheet, or reflective coating protects against UV and physical damage.
Advantages & Considerations
Advantages
- Proven system — over 100 years of performance history
- Multi-ply design provides excellent waterproofing redundancy
- Gravel surface provides fire resistance and UV protection
- Excellent foot traffic resistance
- Long lifespan when properly maintained
Considerations
- Heavy — requires strong structural support
- Installation produces fumes from hot asphalt
- More labor-intensive than single-ply systems
- Leak detection can be difficult in multi-ply systems
What Makes Built-Up Roofing (BUR) Stand Out
Multi-Ply Construction
Three to four alternating layers of asphalt and reinforcing fabric create a monolithic waterproof membrane with built-in redundancy.
Gravel Ballast
Embedded gravel protects the membrane from UV degradation, provides fire resistance, and adds weight to resist wind uplift.
Smooth Coat Option
For a cleaner look and easier maintenance, a smooth asphalt flood coat with reflective coating can replace traditional gravel.
Cold-Applied Systems
Modern cold-applied adhesives eliminate the need for hot kettles, reducing fumes and fire risk during installation.
See Built-Up Roofing (BUR) Up Close
Multi-ply BUR system being installed on a commercial building
Gravel ballast providing UV protection and fire resistance
Finished built-up roof with smooth flood coat
Common Questions About Built-Up Roofing (BUR)
Is built-up roofing still a good choice for commercial buildings?
Absolutely. BUR remains one of the most durable flat roof systems available. While newer single-ply options have gained popularity, many building owners still prefer BUR for its proven track record and superior waterproofing.
Can a gravel roof be converted to a different system?
Yes. When a BUR roof reaches end of life, the gravel can be removed and a new system — whether BUR, modified bitumen, or TPO — can be installed. We evaluate the most cost-effective approach for each building.
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