What Is BUR Roofing? A Comprehensive Guide to Built-Up Roofing Systems
BUR roofing, short for Built-Up Roofing, is one of the most traditional and widely used roofing systems designed for flat or low-slope roofs. It consists of multiple layers of bitumen and reinforcing fabrics, providing durable, waterproof protection. BUR roofing has been trusted in commercial and industrial buildings for decades due to its proven longevity and excellent resistance to weather elements.
| Feature | Description |
|---|---|
| Full Form | Built-Up Roofing |
| Main Components | Bitumen layers, reinforcing fabrics, gravel or mineral surface |
| Typical Uses | Flat and low-slope roofs, commercial buildings, industrial facilities |
| Lifespan | 15 to 30 years depending on installation and maintenance |
| Advantages | Weather-resistant, durable, cost-effective, fire-resistant |
How Built-Up Roofing (BUR) Systems Work
Built-Up Roofing systems are constructed by alternating layers of bitumen and reinforcing fabrics, often called plies, which are then topped with a protective layer of gravel or mineral granules. The bitumen acts as the waterproofing agent, which is typically asphalt, coal tar, or modified bitumen.
The layers are bonded using hot asphalt or cold adhesive, creating a multilayered membrane. This layering pattern gives BUR roofing its durability and strength, protecting the underlying roof deck from water infiltration, UV radiation, and mechanical damage.
Components of BUR Roofing
Bitumen
Bitumen is the primary waterproofing agent, sourced from refined petroleum or coal tar. It is applied as hot asphalt, mopped onto the roof surface, or as modified bitumen sheets for enhanced flexibility and weather resistance.
Reinforcing Fabrics
These fabrics, usually fiberglass or organic felt, provide strength and stability to the roofing membrane. They also distribute roof stresses evenly and improve the roof’s resistance to cracking and tearing.
Surfacing Materials
The top surface is finished with gravel, slag, or mineral granules. This surface protects the bitumen layers from UV damage, weathering, and mechanical wear, increasing the overall lifespan of the roofing system.
Types of BUR Roofing Systems
- Asphalt-Based BUR: Uses asphalt as the bitumen layer, commonly applied hot. Affordable and widely used in commercial roofing.
- Coal Tar Pitch BUR: Known for superior waterproofing and chemical resistance but less common today due to environmental concerns.
- Modified Bitumen BUR: Incorporates polymers for enhanced flexibility and UV resistance, often applied in sheets with heat or adhesive.
Benefits of BUR Roofing
- Durability: Multiple layers provide excellent resistance to punctures, wind uplift, and foot traffic.
- Waterproofing: Bitumen layers create a strong, continuous waterproof membrane.
- Fire Resistance: The gravel surfacing and bitumen composition contribute to fire retardance.
- Cost-Effectiveness: Installation and maintenance costs are generally lower compared to some modern roofing alternatives.
- Proven Track Record: BUR has been used in roofing for over a century, proving long-term reliability.
Common Applications of BUR Roofing
Buildup Roofing is preferred for commercial, institutional, and large industrial buildings, especially those with flat or low-sloped roofs. It is suitable for:
- Warehouses and factories
- Retail stores and shopping malls
- Schools and universities
- Hospitals and government buildings
- Apartment complexes with roof decks
Installation Process of Built-Up Roofing
The installation of BUR roofing requires specialized skills and equipment. The process includes:
- Roof Deck Preparation: The existing roof deck must be clean, dry, and structurally sound.
- Application of Bitumen and Base Sheet: A primer or adhesive is applied, followed by the first bitumen layer and base felt sheet.
- Layering: Multiple alternating layers of bitumen and reinforcing fabric plies are applied using hot asphalt or cold adhesives.
- Top Surfacing: A protective layer of gravel, slag, or mineral granules is spread to shield the membrane from UV rays and mechanical damage.
Maintenance Tips for BUR Roofing
Proper maintenance of BUR roofing can significantly extend its lifespan. Key recommendations include:
- Regular Inspections: Check for cracks, blisters, or punctures especially after severe weather events.
- Cleaning Drainage Areas: Ensure drains and gutters are free of debris to prevent water buildup.
- Repair Promptly: Address small damages immediately to prevent leaks and deterioration.
- Seal Coating: Apply reflective coatings to reduce UV damage and heat absorption.
- Professional Maintenance: Schedule routine inspections and servicing by roofing professionals.
Comparing BUR Roofing with Other Commercial Roofing Systems
| Feature | BUR Roofing | Modified Bitumen | EPDM Rubber Roofing | TPO Roofing |
|---|---|---|---|---|
| Installation Type | Hot application of layers | Sheet-based with heat/adhesive | Sheet membrane, adhesive or ballasted | Single-ply membrane, heat-welded seams |
| Lifespan | 15-30 years | 15-20 years | 20-30 years | 15-25 years |
| Durability | High resistance to punctures and UV | Good flexibility and UV resistance | Good chemical resistance | Good UV protection and energy efficiency |
| Maintenance | Moderate | Low to moderate | Low | Low |
| Cost | Moderate | Moderate to high | Moderate | Moderate to high |
Environmental Considerations of BUR Roofing
While BUR roofing delivers durability, traditional systems often use petroleum-based bitumen, which has environmental concerns. Newer BUR systems incorporate modified bitumen and more sustainable surfacing materials to reduce environmental impact.
Recycling old BUR roofing materials is possible but requires specialized handling. Advancements in green roofing combine BUR with reflective coatings or vegetative layers to enhance energy efficiency and minimize urban heat island effects.
Choosing the Right Roofing Contractor for BUR Installation
Installation quality has a direct impact on BUR roofing performance. Choosing a reputable contractor is crucial. Look for:
- Experience with BUR systems
- Proper licensing and insurance
- Positive customer reviews and references
- Use of quality materials and adherence to manufacturer guidelines
- Comprehensive warranty options
Reliable installation ensures long-lasting protection and helps maximize your investment in BUR roofing.