Aspiring roofing professionals stepping into the roofing industry are often confronted with a myriad of roofing systems and terminologies. One such roofing system that stands as a cornerstone in the roofing industry is the Built-Up Roofing (BUR) system. In this guide, we’ll delve deep into what is a built up roof, its components, advantages, installation process, and why it remains a fundamental choice in commercial roofing projects. Let’s get started.
What is a Built Up Roof (BUR)?
Built-Up Roofing, commonly referred to as BUR, is a time-tested roofing system that has been around for over a century. It is composed of multiple layers of reinforcing fabric, usually fiberglass or organic felt, embedded in bitumen – a blend of asphalt and either coal tar or asphalt.
Components of a Built-Up Roofing System
- Base Sheet: The base sheet provides the initial waterproofing layer and serves as the foundation for subsequent layers.
- Ply Sheets: These are the reinforcing layers that provide strength and durability to the roofing system. They are typically made of fiberglass or organic felt.
- Bitumen: Bitumen acts as the adhesive that holds the layers together, providing waterproofing and weatherproofing capabilities.
- Surfacing: The final layer of the BUR system, which can consist of gravel, mineral granules, or a reflective coating, providing protection from UV rays and weathering.
Advantages of Built-Up Roofing
- Proven Durability: BUR systems have a long track record of durability and longevity, making them a reliable choice for commercial roofing projects.
- Weather Resistance: The multiple layers of bitumen and reinforcing fabric provide excellent resistance to weather elements such as rain, wind, and hail.
- Low Maintenance: Once installed, BUR systems require minimal maintenance, reducing long-term maintenance costs for building owners.
- Fire Resistance: Depending on the type of bitumen used, BUR systems can offer excellent fire resistance, adding an extra layer of safety to the building.
How to Install Built Up Roof
The following is a step-by-step guide that you should follow to install built-up roof.
Surface Preparation
Before the installation of a Built-Up Roofing (BUR) system begins, thorough surface preparation is essential. This involves inspecting the roof deck to ensure it is structurally sound and free of any debris, moisture, or existing roofing materials that could compromise the integrity of the new roof. Any damaged or deteriorated sections of the roof deck are repaired or replaced as needed. Additionally, proper drainage systems must be in place to prevent standing water on the roof, which can lead to leaks and premature deterioration.
Base Sheet Installation
The first step in installing a BUR system is laying down the base sheet. This sheet serves as the initial waterproofing layer and provides a smooth surface for the subsequent layers to adhere to. The base sheet is typically attached to the roof deck using mechanical fasteners or hot asphalt, depending on the specific installation method chosen.
Layer Application
Once the base sheet is in place, the next step is to apply the reinforcing layers, also known as ply sheets. These sheets are typically made of fiberglass or organic felt and are saturated with hot asphalt or cold adhesive before being laid out on the roof surface. Each ply sheet is then embedded in hot bitumen using a mop or roller to ensure proper adhesion and waterproofing. The number of ply layers applied depends on the specific requirements of the project and the desired level of durability.
Interply Mastic and Flashing Installation
After each layer of ply sheets is installed, interply mastic may be applied between the layers to enhance waterproofing and bonding. Flashing, which consists of metal strips or sheets, is also installed around roof penetrations such as vents, chimneys, and skylights to prevent water infiltration at these vulnerable points. Flashing is secured in place using mechanical fasteners or hot asphalt.
Final Surfacing
Once all ply layers and flashing are in place, the final step is to apply the surfacing material to the roof. This can consist of gravel, mineral granules, or a reflective coating, depending on the specific requirements of the project and the desired aesthetic appearance. The surfacing material provides additional protection from UV rays, weathering, and mechanical damage, while also helping to improve the overall fire resistance of the roof system.
Quality Assurance and Inspection
Throughout the installation process, quality assurance measures are implemented to ensure that each component of the BUR system is installed correctly and according to industry standards. Roofing professionals conduct regular inspections to check for any defects, inconsistencies, or areas that may require additional attention. This attention to detail is crucial for ensuring the long-term performance and durability of the BUR system.
Why Choose Built-Up Roofing?
- Longevity: BUR systems can last 20 years or more with proper maintenance, offering excellent return on investment for building owners.
- Versatility: BUR systems can be installed on a variety of roof slopes and shapes, making them suitable for a wide range of commercial buildings.
- Cost-Effectiveness: While initial installation costs may be higher than some other roofing systems, the long-term durability and low maintenance requirements of BUR systems make them a cost-effective choice over time.
Read More: What Are Roof Shingles Made Of?
Conclusion
Built-Up Roofing (BUR) remains a foundational choice in the roofing industry, offering durability, weather resistance, and longevity. For aspiring roofing professionals, understanding the components, advantages, and installation process of BUR systems is essential for building a successful career in the roofing industry.
