What is the function of the bitumen in a BUR system?

The function of bitumen in a Built-Up Roofing (BUR) system is primarily to bond the layers of roofing material and provide waterproofing. Bitumen serves as a vital adhesive that holds the multiple layers together, which are typically made up of alternating layers of felt and bitumen. This bonding ensures that the roofing system remains cohesive and maintains its integrity against environmental factors like rain, snow, and ice.

Moreover, bitumen plays a crucial role in creating a waterproof barrier; it prevents water from penetrating the roofing structure, which is essential for protecting the underlying building materials from moisture damage. The properties of bitumen, including its viscosity and flexibility, contribute to its effectiveness in these roles, making it indispensable for the performance and longevity of BUR systems.

The other aspects of roofing, such as insulation, sound-proofing, or aesthetic appearance, are important, but they are not the primary functions of bitumen in this context. Insulation in a roofing system often comes from other materials that are specifically designed for temperature regulation, while sound barriers typically involve additional materials to dampen noise. Aesthetic considerations usually relate to the finishing materials applied over a BUR system rather than the bitumen itself.