What Is Built Up Roofing?

Built up roofing (BUR) consists of multiple layers of bitumen and reinforcing fabrics that create a finished membrane. Bitumen used can be either asphalt, coal tar, or cold-applied adhesive. The bitumen serves as the adhesive and waterproofing agent, while the reinforcing fabrics, commonly made from fiberglass or polyester, provide strength and stability. The top surface is typically covered with gravel or other granular materials, which protect against UV rays and weather damage.

Built up roofing is applied by alternating layers of bitumen and reinforcing fabrics over the roof deck. The process begins with the installation of a base sheet, followed by multiple layers of roofing felts that are adhered with bitumen. These layers are either mopped with hot bitumen or applied using cold adhesive methods. The final layer is a top coat of bitumen into which gravel or another surfacing material is embedded for additional protection and durability.

Built up roofing offers excellent waterproofing capabilities, high tensile strength due to its multiple layers, and good resistance to thermal shock. It is highly durable and can last up to 30 years with proper maintenance. BUR is also fire-resistant and can be customized with various top surfacing options, including reflective coatings or gravel, which can enhance its energy efficiency by reflecting UV rays and reducing cooling costs.

Built up roofing is known for its durability and requires relatively low maintenance. Regular inspections and basic maintenance, such as cleaning debris and checking for damage, are recommended to extend its lifespan. Any detected issues, like cracks or blisters, should be repaired promptly to prevent leaks. Periodic reapplication of the surfacing layer may also be necessary to maintain its effectiveness against UV rays and weathering.

While traditional built up roofing materials are not the most environmentally friendly due to the use of petroleum-based products like asphalt and coal tar, it is possible to select more eco-friendly options. For example, using recycled materials for the aggregate layer or choosing bitumen alternatives that emit lower volatile organic compounds (VOCs) can reduce environmental impact. Furthermore, the longevity of BUR minimizes the frequency of roof replacement, contributing to sustainability.

Built up roofing is highly resistant to water damage and can perform well under various weather conditions, including heavy rains, high winds, and extreme temperatures. The multiple layers of bitumen and fabric enhance its ability to resist mechanical damage and thermal shock, making it a reliable choice for areas with severe weather patterns. However, it is crucial to ensure that the roof is properly maintained and inspected regularly to handle extreme weather effectively.

Yes, built up roofing can be installed over existing roofing systems if the structure can support additional weight and the existing roof is in good condition. This approach can save time and reduce costs associated with roof tear-off and disposal. However, a thorough inspection by a professional is essential to ensure that the existing roof deck is sound and that there are no moisture issues that could compromise the new roofing system.

Built up roofing is ideal for buildings with low-slope or flat roofs, where water pooling tends to occur. It is commonly used on commercial and industrial buildings due to its capacity to cover large areas cost-effectively. Schools, warehouses, and office buildings often benefit from the durability and protective qualities of BUR systems. Residential applications are less common but can be suitable for homes with flat roofs.

The cost of built up roofing can vary based on several factors including material choices, labor rates, roof accessibility, and the overall size of the roof. On average, BUR systems are cost-effective for large commercial roofs due to the materials’ availability and the relatively straightforward installation process. Pricing might be higher compared to single-ply membranes, but the longevity and durability of built up roofing often justify the initial investment.

Repairing built up roofing typically involves locating the breach or damaged area, cleaning it, and then applying a patch of similar bituminous material. For larger issues, such as blisters or extensive cracks, additional layers of roofing felt may be added, followed by a proper amount of bitumen. It’s important for repairs to be carried out by professionals who can ensure that the integrity of the roof is maintained, preventing further damage and leaks.