Built-up roofing (BUR) systems have been a staple in the commercial roofing industry for over a century, known for their durability and effectiveness in protecting large flat or low-slope roof surfaces. As with any roofing system, BUR comes with its set of advantages and disadvantages, making it crucial for property owners and developers to understand these aspects thoroughly before making a decision.
One of the primary advantages of built-up roofing is its proven track record of durability and longevity. A typical BUR system consists of multiple layers of bitumen and reinforcing fabrics that create a finished membrane. This multi-layered approach provides a high level of protection against water, making BUR an excellent waterproofing solution. The redundancy of layers ensures that even if one layer is compromised, the underlying layers continue to provide protection. This layered structure contributes to the BUR’s longevity, with many roofs lasting 15 to 30 years, and some even longer with proper maintenance.
Another significant benefit of built-up roofing is its robust resistance to foot traffic. This feature is particularly important for commercial buildings where the roof may need to accommodate regular maintenance for HVAC systems and other utilities. The toughness of a BUR system is able to withstand such traffic without sustaining damage, which is a crucial consideration for commercial buildings.
BUR systems also offer excellent UV protection. The top layer, often made of gravel or mineral blends, reflects UV rays and helps protect the roof from the deteriorating effects of sunlight. This UV resistance not only prolongs the roof’s life but also contributes to reducing the building’s cooling costs, as it helps maintain a cooler roof temperature.
However, built-up roofing is not without its downsides. One of the most significant disadvantages is the installation process, which can be more labor-intensive and time-consuming compared to other roofing types. The installation involves the application of hot bitumen, which requires specialized skills and equipment. This process can emit fumes and odors that may be disruptive, particularly in densely populated areas or in buildings that are occupied during the roofing work.
Another con of BUR is its weight. The multiple layers that provide durability and protection also add significant weight to the roof structure. This means that the building must have enough structural support to handle the load, which may not be the case in older or less robustly constructed buildings. In such cases, additional structural reinforcement might be necessary, adding to the overall cost.
Furthermore, BUR systems can be more susceptible to water ponding. Flat or low-slope roofs inherently have less efficient water drainage, and if not properly designed, BUR roofs can allow water to pool, leading to potential leaks and degradation over time. Effective drainage systems and regular maintenance are essential to mitigate this issue.
Lastly, the cost factor is a critical consideration. While BUR systems are generally cost-effective in the long run due to their durability, the initial installation cost can be higher than some other roofing options. This is due to the labor-intensive nature of the installation process and the materials used.
In conclusion, built-up roofing systems offer a robust and durable solution for commercial buildings, particularly those with flat or low-slope roofs. Their longevity, resistance to foot traffic, and UV protection make them a compelling choice. However, considerations around installation complexity, weight, water drainage, and cost must be carefully weighed. For property owners and developers, understanding these pros and cons is key to making an informed decision that aligns with the specific needs and constraints of their commercial property.