Built-up roofing (BUR) is a widely used flat roofing system known for its durability and weather resistance. This multi-layered roofing solution has been a staple in commercial and industrial buildings for decades. Whether you’re considering a new installation or need to maintain an existing BUR system, understanding its structure, benefits, and professional installation process is crucial.
Key Takeaways
- Built-up roofing Systems (BUR) are designed for low-slope or flat roofs and consist of multiple layers of bitumen and reinforcement materials that enhance durability and waterproofing.
- Two main types of bitumen used in BUR include asphalt and coal tar, with asphalt being more prevalent due to its effective waterproofing capabilities and various application methods.
- While BUR systems offer numerous benefits, such as longevity, waterproofing, and low maintenance requirements, they also present challenges during installation and have higher initial costs compared to other roofing options.
Understanding Built-Up Roofing Systems
Built-up roofing (BUR) is a roofing system composed of multiple layers of bitumen (asphalt or coal tar) alternated with reinforcing fabrics to create a highly durable and watertight membrane. The layers are then topped with a protective surface such as gravel, a mineral cap sheet, or a reflective coating to enhance weather resistance and energy efficiency.
Because BUR systems involve multiple layers of hot or cold-applied asphalt, professional installation is essential. Expert roofers ensure proper layering, adhesion, and sealing to create a long-lasting, watertight roof that can withstand years of exposure to the elements.
Read more: Steps to Choose the Right Roofing Contractor
The Layers of a Built-Up Roof System
The construction of a Built-up Roof system involves multiple layers, each serving a specific purpose. The base sheet is the first layer, acting as an initial waterproof barrier and foundation. It is typically installed over insulation or a cover board, providing a solid base for the subsequent layers.
The ply sheets, which are installed over the base sheet, increase the roof’s durability and resistance to thermal shock and moisture. These ply sheets are commonly made of hot asphalt and fabrics like fiberglass, enhancing the overall strength of the roofing system.
The final layer is the surfacing material, typically gravel, which not only adds durability but also protects the underlying layers from UV radiation and other environmental factors.
Types of Bitumen Used in Built-Up Roofing
The ability of Built Up Roofing Systems to prevent water infiltration is heavily dependent on the specific kind of bitumen employed. Asphalt and coal tar constitute the primary variants, with asphalt being more prevalent in modern applications. Despite its capacity for self-repair, coal tar has become less popular owing to potential chemical burns during installation.
Three varieties of asphalt are utilized within BUR systems: hot asphalt, cold asphalt, and torch-down methods. Each category offers distinct application processes and advantages while sharing a common goal – establishing an impervious seal against moisture.
Within any built-up roofing system, bitumen stands as the key component responsible for sealing out water. Hence, it plays an indispensable role in dictating the roof’s waterproofing effectiveness.
History and Evolution of Built-Up Roofing
Dating back to the 1800s, Built-up Roofing (BUR) systems are among the most time-honored roofing technologies still employed in modern times. Initially, coal tar and pitch were key components of BUR due to their robust waterproofing properties and enduring nature.
As time has progressed, BUR systems have undergone substantial improvements both in the materials used and in the installation processes. These advancements have bolstered their strength and functionality while simplifying application procedures, leading to widespread adoption for commercial structures from the 1970s onward. The emergence of modified asphalt as a material greatly advanced BUR’s development by enhancing previous iterations.
Installation Process of Built-Up Roofing
Installing a Built-Up Roofing (BUR) system is a detailed process that requires expertise to ensure durability and weather resistance. The multi-layered construction enhances waterproofing and structural integrity, making it a reliable choice for commercial buildings.
- Secure the Base Sheet – Attach the base sheet to the roof deck using roofing nails or mechanical fasteners. This acts as the foundation for the BUR system.
- Apply Bitumen and Reinforcing Layers – Alternate layers of bitumen (hot asphalt, coal tar, or cold-applied adhesive) and roofing felt (ply sheets) to build up the roofing system.
- Install the Surfacing Layer – Apply a final protective layer such as gravel, a mineral cap sheet, or a reflective coating to improve durability and UV resistance.
- Final Waterproofing Seal – Ensure all layers are properly bonded and sealed to create a watertight system that enhances longevity and performance.
Hot Asphalt Application Method
During the installation process of a built-up roofing system, hot asphalt is spread over an initial base sheet. Following this application, a reinforced felt, known as a ply sheet, is laid down to enhance support and resilience. The utilization of hot asphalt ensures formidable bonding and establishes a waterproof seal that significantly reinforces the integrity of the roofing system.
Although applying this method effectively yields a sturdy and enduring roof solution, it demands meticulous execution due to the involvement of elevated temperatures. Nevertheless, despite the difficulties encountered in its implementation, hot asphalt persists as a favored approach for securing a robust and impermeable roof surface.
Cold Applied Adhesive Method
Utilizing cold-applied adhesive as a bonding agent for the layers in a Built-Up Roofing (BUR) system presents a less dangerous option compared to employing hot asphalt. By adopting this technique, the necessity for elevated temperatures is removed, which subsequently diminishes the potential for burns or additional injuries.
Even though this approach carries reduced risks, it still demands experienced workers who can competently execute its application and guarantee effective adhesion.
Benefits of Built-Up Roofing Systems
Built-up roofing (BUR) systems are a trusted choice for commercial properties due to their exceptional durability, long lifespan, and superior protection. Designed to withstand extreme weather conditions, these multi-layered systems provide unmatched performance and can last for decades with proper care, making them a smart long-term investment.
One of the standout advantages of BUR systems is their superior waterproofing. The combination of bitumen and reinforcement layers forms a highly effective barrier against moisture, preventing leaks and preserving the structural integrity of the building. Additionally, these roofing systems require minimal maintenance, offering cost efficiency and peace of mind to property owners over time.
Read more: How Dayton Weather Impacts Your Roof and What to Do About It
Longevity and Durability
Built-up roofing systems are renowned for their exceptional strength and extended service life. With professional installation and regular maintenance, a BUR roof can last well beyond 30 years. Its robust, multi-layered construction provides excellent resistance against harsh weather conditions and enhances thermal insulation, making it an ideal choice for commercial buildings.
To maintain peak performance, it is recommended that a protective coating be applied every five years. Reflective coatings not only preserve the integrity of the roofing system but also enhance energy efficiency by reducing heat absorption. This results in lower cooling costs and improved energy savings, making BUR an excellent solution for long-term performance and sustainability.
The combination of resilience, efficiency, and long-lasting protection makes Built-Up Roofing an outstanding investment for property owners seeking a reliable and cost-effective roofing solution.
Superior Waterproofing Capabilities
One of the key benefits of Built-Up Roofing (BUR) is its outstanding ability to prevent water penetration. Its layered construction forms a seamless and watertight surface that remains effective in all types of weather. This design helps eliminate vulnerabilities that can lead to leaks, ensuring long-term protection for the building structure.
Additionally, the top layer of a BUR system enhances UV resistance, reducing wear and extending the roof’s lifespan. This combination of waterproofing and durability makes BUR an excellent choice for businesses seeking maximum protection against the elements.
Minimal Maintenance for Long-Term Reliability
Built-up roofing systems are designed for low maintenance, providing property owners with long-term reliability. With routine inspections conducted by professional roofing specialists, potential concerns can be identified early to maintain the system’s integrity. Biannual inspections help ensure peak performance, allowing the roof to remain in optimal condition for years to come.
This minimal maintenance requirement makes BUR a cost-effective roofing solution, reducing the need for frequent repairs while offering long-lasting durability and peace of mind.
Comparing Built Up Roofing with Other Roof Types
When selecting a roofing system for your commercial property, it’s critical to evaluate various choices to identify the most suitable one. Frequently assessed against each other are Built Up Roofing Systems (BUR), modified bitumen roofs, single-ply roofs, and metal roofs. These types of roofing possess unique characteristics along with their respective pros and cons. Hence, comprehending their comparative performance is key.
For flat-roofed commercial buildings in particular, BUR systems, modified bitumen roofs, and single-ply solutions present specific advantages tailored for certain uses. Acknowledging these differences is imperative when deciding on the appropriate option for your commercial building’s needs.
BUR vs. Modified Bitumen Roofing
Roof systems that utilize modified bitumen involve a cap sheet, which can either be torched down or self-adhered to the base sheet. This design provides increased flexibility and simplifies installation when compared with conventional BUR (Built-Up Roofing) systems. These modified bitumen roofing structures are less redundant than traditional ones, posing an elevated risk of water leakage in case they get punctured.
Conversely, BUR roof systems primarily incorporate asphalt-based components that contribute to their robustness but may come at a higher expense relative to certain modified bitumen options. The layered construction inherent in BUR setups enhances protection and redundancy, affirming their status as trustworthy selections for sustained performance over time.
BUR vs. Single Ply Roofing
Roofing systems that are single-ply, like EPDM, often require repairs more regularly than BUR systems. They have a higher susceptibility to damage from punctures and usually don’t offer as much energy efficiency as BUR options do. Although they benefit from being lightweight and having excellent UV resistance, in terms of long-term cost-effectiveness, single-ply roofing solutions tend not to match the durability and extended lifespan characteristic of BUR roofing systems.
BUR vs. Metal Roofing
Metal roofing often boasts a superior lifespan compared to BUR systems, with its durability extending beyond 70 years. Nevertheless, BUR roofing can offer enhanced waterproofing capabilities, particularly when the metal roofing system uses exposed fasteners, which may be prone to leaks.
The robust nature of BUR makes it ideal for roofs that see considerable foot traffic due to frequent maintenance needs or access requirements. It’s designed to endure such conditions effectively.
Maintenance and Repair of Built Up Roofing Systems
Proper upkeep is essential for ensuring the longevity and functionality of a built-up roofing system. Regular professional roof inspections help detect potential issues early, preventing structural damage caused by debris accumulation and standing water. Experienced roofing specialists can clear debris, trim overhanging tree branches, and assess the roof’s condition to ensure it remains structurally sound.
After severe weather events, it’s crucial to have professionals examine the roof for signs of ponding water, cracks, or other vulnerabilities. Prompt attention to these issues minimizes the risk of long-term damage. If problems arise, expert repairs such as sealing cracks, reinforcing seams, and restoring weakened areas are necessary to prevent further deterioration. Routine maintenance, combined with the application of protective coatings by trained professionals, can extend the lifespan of a BUR system by an additional 15-20 years.
Read more: 7 Key Signs Your Roof Needs Repair
Common Repairs and Issues
Built-Up Roofing Systems may experience several issues over time, including:
- Seam degradation can lead to water infiltration if not properly maintained.
- Standing water accumulation may weaken structural integrity if left unaddressed.
- Surface bubbling, which increases the risk of punctures due to foot traffic.
Professional roofers are equipped to assess and repair these issues, ensuring the roof remains watertight and structurally sound. Technicians can reinforce aging seams, apply specialized coatings, and replace severely damaged sections to prevent leaks and prolong the roof’s performance. Engaging experienced professionals for routine evaluations and timely repairs minimizes disruptions while maximizing cost efficiency.
Preventative Maintenance Tips
Preventative maintenance performed by experienced professionals is crucial for maximizing the lifespan of a Built Up Roofing System. Routine inspections allow for early identification of necessary repairs, reducing the risk of extensive damage. Roofing specialists can remove debris, trim overhanging branches, and ensure proper drainage to maintain the system’s integrity.
For aging BUR systems, applying an elastomeric protective coating enhances durability and extends longevity by 15-20 years. By scheduling regular maintenance with a professional roofing service, commercial property owners can ensure their roofing system remains in optimal condition while avoiding costly repairs.
When to Choose Built-Up Roofing for Your Commercial Property
Built-up roofing systems are an excellent choice for commercial buildings with low-slope or flat roofs. Their multi-layered construction effectively manages water runoff while providing superior support for rooftop gardens, solar panels, or other structural additions. Their durability makes them a reliable solution for properties in regions prone to extreme weather conditions.
Industrial facilities requiring high fire resistance benefit significantly from BUR systems due to their inherent fire-retardant properties. Additionally, historic buildings can maintain their architectural integrity while gaining modern performance benefits with a properly installed BUR system. For businesses prioritizing energy efficiency, professional roofing contractors can apply reflective coatings to enhance heat resistance—an advantage particularly beneficial in warmer climates.
Summary
Built-Up Roofing Systems are an excellent choice for low-slope and flat roofs, providing a durable, reliable, and long-lasting roofing solution. Their multi-layered design ensures superior waterproofing and resilience against extreme weather, making them a preferred option for commercial properties. While the installation process requires specialized expertise and comes with higher initial costs, the long-term benefits—such as durability, low maintenance, and superior performance—make them a worthwhile investment.
Schaefer and Company, a reputable roof contractor serving Dayton, is equipped with extensive industry experience to guide you in selecting the ideal BUR system for your commercial property. Our skilled team is dedicated to delivering top-notch roofing solutions tailored to your specific requirements. Contact us today to discover how Built Up Roofing Systems can transform your commercial property!
Frequently Asked Questions
1. How does a Built Up Roofing system handle foot traffic compared to other commercial roofs?
Built-Up Roofing (BUR) is designed to withstand heavy foot traffic due to its multiple reinforced layers, making it ideal for buildings that require frequent rooftop access for maintenance or equipment.
2. Can a Built Up Roofing system be customized for better energy efficiency?
Yes, reflective coatings or cool roof materials can be added to BUR systems to improve energy efficiency, reduce heat absorption, and lower cooling costs in warmer climates.
3. What are the key signs that a Built Up Roofing system needs repairs?
Common indicators include bubbling or blistering on the surface, seam separation, and pooling water, all of which should be addressed promptly to prevent further damage.
