What is a built up roof?

A built-up roof (BUR) is a type of flat or low-slope roofing system commonly used on commercial and industrial buildings. It is made up of multiple layers of roofing felt or fiberglass matted together with bitumen, and then covered with a layer of gravel or a reflective coating.

Some key components of a built-up roof include:

1. Insulation: BURs typically include a layer of insulation beneath the roofing membrane to provide thermal protection and improve energy efficiency.
2. Surfacing: The top layer of a BUR can be covered with gravel, reflective coating, or other materials to protect the underlying layers from UV rays, weathering, and foot traffic.
3. Membrane: The multiple layers of roofing felt or fiberglass are impregnated with bitumen (asphalt) to create a durable, waterproof membrane that seals out moisture.

Built-up roofs have a long lifespan of 20-30 years or more when properly maintained. They are resistant to fire, wind, and punctures, making them a reliable choice for flat roofs in areas with extreme weather conditions. However, BUR installation can be labor-intensive and messy due to the hot tar and gravel used in the process.

Overall, built-up roofs are a cost-effective and durable option for commercial and industrial buildings that require a long-lasting, low-maintenance roofing solution.