[PDF] Hot Built-Up Roofing

What is a built-up roof?

This more properly refers to roofs made with coal tar pitch, which was used in almost all built-up roofs for the first 100 years after modern built-up roofing was invented (around 1860). Asphalt became a popular alternative to coal tar pitch in the 1950’s, and today almost all built-up roofs are made with asphalt.

What is hot asphalt roofing?

Hot asphalt roofing is a type of built-up roofing in which asphalt forms the waterproofing component of the roof membrane. During application, the hot, liquid asphalt is referred to by the roofers simply as “hot”, as in “I stepped in the hot”. Built-up roofs made with asphalt are often called “tar and gravel” roofs.

Can a built-up roof be repaired?

It is possible to repair the built-up roof if the damage is not too extensive. Built-up roofing does not last forever, but it will require some maintenance and the occasional repair along the way. Some BUR damage is too much to be repaired, which requires replacement.

What is a gravel-surfaced built-up roof?

View of a gravel-surfaced built-up roof. What is a Built-up Roof? A built-up roof is a type of “flat” or low-sloped roof made up of multiple layers of bitumen (asphalt or coal tar pitch) and reinforcing felts. Typical built-up roofs have three to five layers, called “plies”.