Built-Up Roofing (BUR) is a popular and durable roofing solution widely used in commercial and industrial buildings across the United States. Known for its multi-layered construction, BUR offers exceptional protection against weather and environmental damage. This article delves deep into the components, installation methods, benefits, and maintenance of BUR systems, providing valuable information for property owners, contractors, and architects.
| Aspect | Details |
|---|---|
| Definition | Multi-layered roofing system using asphalt and reinforcing fabrics |
| Common Uses | Commercial, industrial flat or low-slope roofs |
| Key Components | Asphalt or coal tar, felt or fiberglass membranes, surfacing materials |
| Average Lifespan | 15-30 years with proper maintenance |
| Main Benefits | Waterproofing, UV protection, durability, and fire resistance |
What Is Built-Up Roofing (BUR)?
Built-Up Roofing, often abbreviated as BUR, is a traditional roofing method involving multiple layers of roofing felt or fabric alternated with adhesive hot asphalt or coal tar. This layered approach creates a robust, waterproof membrane designed primarily for flat or low-slope roofs. BUR systems have been a trusted roofing solution for decades due to their proven durability and resistance to harsh weather conditions.
Components of Built-Up Roofing Systems
The strength and longevity of BUR systems stem from their unique combination of materials:
- Base Sheets: Heavy-duty felts or fiberglass mats provide the foundational layers.
- Adhesive Layers: Hot asphalt or coal tar bind the layers together and provide waterproofing.
- Surfacing: The top layer often includes gravel, mineral granules, or reflective coatings that protect against UV damage and physical wear.
Installation Process of BUR Systems
BUR installation is a meticulous process that plays a significant role in its performance and lifespan. The key steps include:
- Roof Deck Preparation: The roofing surface must be clean, dry, and structurally sound.
- Laying Base Sheets: The first layer of felt or fabric is positioned firmly on the roof.
- Applying Hot Asphalt or Coal Tar: This adhesive substance is heated and spread evenly to bond successive layers.
- Layering Multiple Felt Sheets: Typically 3 to 5 sheets are applied for adequate thickness and durability.
- Adding Surfacing Material: A final protective layer of gravel or reflective coating is embedded while the adhesive is still hot.
Professional installation is crucial. Improper layering or insufficient adhesive can lead to leaks and premature failure.
Benefits of Using Built-Up Roofing
BUR systems offer multiple advantages that make them a preferred choice for many commercial buildings:
- Durability: Multiple layers provide strength and resistance to punctures, wind, and other elements.
- Waterproofing: Hot asphalt creates a seamless, watertight membrane.
- Fire Resistance: Coal tar and asphalt layers reduce fire risk.
- Cost-Effectiveness: While initial costs vary, BUR requires minimal maintenance, resulting in lower lifecycle expenses.
- UV Protection: Gravel or reflective coatings protect the roof from sun damage and thermal degradation.
Common Types of Built-Up Roofing Materials
BUR systems can utilize various materials based on budget, climate, and specific building requirements. Notable types include:
| Material | Description | Advantages |
|---|---|---|
| Asphalt-Based Felt | Traditional felt saturated with asphalt | Cost-effective and widely available |
| Coal Tar | High molecular weight tar with superior waterproofing | Excellent chemical resistance and durability |
| Fiberglass Mat | Reinforced with glass fibers | Enhanced tensile strength and fire resistance |
Maintenance and Longevity of Built-Up Roofing
Regular upkeep is essential to maximize the lifespan of BUR systems. Recommended maintenance measures include:
- Routine Inspections: Semi-annual and post-storm checks for cracks, blisters, or punctures.
- Debris Removal: Ensuring the roof surface is free from leaves, dirt, and standing water.
- Reapplying Surfacing: Gravel or protective coatings may need replenishment to maintain UV protection.
- Prompt Repairs: Addressing minor damage quickly to prevent leaks.
With proper care, BUR roofs can last 15 to 30 years, offering reliable performance for commercial buildings.
Comparing Built-Up Roofing with Alternative Roofing Systems
While BUR is a standout option for flat and low-slope roofs, other roofing systems may also be considered:
| Roof Type | Built-Up Roofing (BUR) | Modified Bitumen | Single-Ply Membranes |
|---|---|---|---|
| Durability | High due to multiple layers | Moderate to high | Varies by material; generally less durable than BUR |
| Installation | Labor-intensive, hot application | Can be torch-applied or cold-adhesive | Quick, often mechanically attached or adhered |
| Cost | Moderate installation costs | Higher than BUR | Varies, often more expensive upfront |
| Maintenance | Low to moderate | Moderate | Low |
Environmental Considerations for Built-Up Roofing
BUR systems incorporate materials like asphalt and coal tar that have environmental impacts. However, innovation is leading to greener options:
- Recycled Materials: Some BUR felts integrate recycled fibers reducing landfill waste.
- Reflective Surfacing: Cool roof coatings reduce urban heat island effects and improve building energy efficiency.
- Longevity Reduces Waste: Long-lasting BUR roofs decrease the frequency of roof replacements.
Cost Factors Influencing Built-Up Roofing Installation
Several factors affect the overall expense of installing a BUR system, including:
- Roof Size and Complexity: Larger or intricate roofs increase labor and materials costs.
- Material Quality: Premium asphalt or fiberglass can raise prices.
- Labor Expertise: Skilled contractors may charge more but provide higher quality installation.
- Location: Geographic variables like climate and local market rates influence costs.
Common Challenges with Built-Up Roofing and Solutions
Like all roofing systems, BUR has challenges that require attention:
- Weight: BUR roofs are heavier than some alternatives; structural assessment is crucial before installation.
- Installation Hazards: Hot asphalt application poses safety risks, demanding professional handling.
- Cracking or Blistering: Can occur due to trapped moisture or thermal cycling; proper ventilation and quality materials mitigate these issues.
- Maintenance Access: Gravel surfaces can make routine inspections harder; using walk pads can protect the roof.
Frequently Asked Questions About Built-Up Roofing (BUR)
Is Built-Up Roofing Suitable for Residential Homes?
BUR is primarily designed for commercial and industrial buildings with flat or low-slope roofs. It is less common for residential homes with steep roofs.
How Long Does a BUR Roof Last?
With proper maintenance, a BUR roof can last between 15 and 30 years, depending on environmental factors and installation quality.
Can Built-Up Roofing Be Repaired?
Yes, BUR roofs can be patched or resurfaced. Prompt repairs help extend the roof’s service life.
Does BUR Roofing Require Special Inspections?
Regular inspections by roofing professionals are recommended to detect issues early and maintain optimal performance.