Built-Up Roofing (BUR), a time-honored method prevalent in commercial and industrial roofing, is renowned for its durability and effectiveness, particularly on flat or low-slope roofs. This method involves layering materials to create a substantial, protective roofing system. This article delves into the details of BUR methods, outlining the meticulous process that ensures a long-lasting roofing solution.
The foundation of BUR lies in its layered composition. This technique traditionally involves alternating layers of bitumen and reinforcing fabrics, creating a finished membrane. The choice of bitumen, typically either asphalt or coal tar, is crucial. These materials are known for their waterproofing qualities and ability to adhere the layers together.
Preparation is key in BUR roofing. The roof deck must be thoroughly inspected and prepared before installation. Ensuring the deck is clean, dry, and structurally sound is imperative. Any defects in the roof deck, such as moisture or instability, can compromise the integrity of the BUR system. Often, a base sheet is fastened to the roof deck as the initial layer, providing a smooth, stable surface for the subsequent layers.
The installation process of BUR is labor-intensive and requires precision. It starts with the application of the bitumen, which is often heated to a liquid state for easy application. The bitumen serves as a binding agent and waterproofing material. Following the application of each bitumen layer, a reinforcing fabric, typically made of fiberglass or polyester, is rolled out onto the hot bitumen. This fabric reinforcement is crucial, as it provides strength and stability to the roofing system.
Layering is the essence of BUR. The process of alternating bitumen and reinforcing fabric is repeated several times, usually resulting in three to five layers, depending on the roof’s requirements. Each layer needs to be meticulously applied to ensure full coverage and effective bonding. The thickness and number of layers play a significant role in the roof’s durability and lifespan.
The top layer of a BUR system is particularly important as it is exposed to environmental elements. Traditionally, a layer of gravel or mineral granules is embedded in the top coating of bitumen to protect the roof from sunlight, weathering, and mechanical damage. This surfacing layer not only prolongs the life of the roof but also provides fire resistance and enhances the roof’s aesthetic appeal.
Ventilation and insulation are also integral to BUR roofing. Proper ventilation ensures the longevity of the roof by preventing moisture buildup, while insulation helps in maintaining energy efficiency. These elements need to be integrated into the roofing system without compromising the waterproofing and structural integrity of the roof.
Maintenance and repair are essential aspects of BUR roofing. Regular inspections and maintenance can significantly extend the roof’s life. BUR roofs are known for their repairability; damaged sections can often be patched or replaced without the need for a complete roof overhaul.
In conclusion, Built-Up Roofing is a proven, robust roofing method, especially suited for large, flat roof areas. Its multi-layered approach provides exceptional protection and durability. The success of a BUR system lies in the quality of materials used, the precision of the layering process, and the expertise of the installation team. When executed correctly, BUR can offer a reliable, long-term roofing solution, safeguarding buildings against various environmental challenges.