What type of roofing is commonly referred to as "tar and gravel" roofing?

The type of roofing commonly referred to as "tar and gravel" roofing is Built-Up Roofing, often abbreviated as BUR. This roofing system is constructed by alternating layers of bitumen (tar) and reinforcing fabrics, like felts, which are then topped with a layer of gravel to provide durability and weight. The gravel acts as both a protective layer and a UV stabilizer, minimizing the degradation caused by sunlight. BUR systems are known for their flat or low-slope applications, making them a popular choice for commercial buildings.

By understanding this, you can appreciate the practical benefits of BUR roofing, such as its ability to create a watertight seal and its relative low maintenance needs compared to other roofing types.