Which roofing system has more layers?

In evaluating roofing systems, the built-up roofing system is known for its multi-layered construction, which adds to its durability and weather resistance. This system typically consists of multiple layers of felts or fabrics that are alternately bonded with bitumen. Each layer enhances the overall performance of the roofing system by providing additional waterproofing, UV protection, and insulation.

The built-up roofing system is specifically designed to offer long-lasting protection, making it a popular choice for flat or low-slope roofs. The layers create a robust structure that can effectively manage water drainage and withstand various environmental conditions.

In contrast, single-ply roofing systems and TPO (Thermoplastic Olefin) roofing systems generally consist of a single layer of membrane material, which, although effective, does not provide the same level of thickness or layered durability. Modified bitumen roofing may feature a couple of layers, but it still does not reach the complexity and layered nature of built-up roofing.

This multilayer characteristic of the built-up roofing system plays a crucial role in its performance and longevity, setting it apart from the other types mentioned.