What material is often added to the top surface of BUR to enhance durability?

The choice of granules as an additive to the top surface of Built-Up Roofing (BUR) is important due to their many beneficial properties that enhance the durability and performance of the roofing system. Granules provide a protective layer that helps shield the underlying materials from UV radiation, which can lead to degradation over time. Additionally, the granules assist in protecting the roof from physical damage caused by weathering, such as hail or debris.

Furthermore, they contribute to the roofing system's overall aesthetic appeal by coming in various colors and textures, allowing homeowners or building managers to choose options that meet their visual preferences. The use of granules also helps improve the fire resistance of the roofing surface, which is a significant factor in preventing the spread of flames in the event of a fire.

While reflective coatings can also enhance durability by providing UV protection and improving energy efficiency, they serve a different purpose than granules and may not be incorporated in the same way into the BUR system. Similarly, fiberglass is typically used as a reinforcement material in roofing membranes rather than as a top surface; aluminum foil is sometimes utilized for reflective and insulating properties but does not provide the same level of protection or durability as granules do.