What is the main characteristic of a built-up roof system using hot asphalt?

The main characteristic of a built-up roof system using hot asphalt is that it is composed of layers of roofing felt and hot asphalt. This type of roofing system is created by alternating layers of bitumen (hot asphalt) and reinforcing fabrics, such as roofing felt, to form a durable and weather-resistant surface. The multiple layers provide additional strength and enhance the roof's ability to withstand the elements. This method allows for excellent waterproofing and is particularly beneficial in flat or low-slope roof applications.

Unlike methods that rely on magnetic adhesives or metal sheets, built-up roofs with hot asphalt utilize the properties of bitumen to create a cohesive system that effectively seals the roof against moisture and provides durability over time. This layering technique is essential for the optimal performance and longevity of built-up roofing systems.