This is one of the most popular types of “flat roof” and offers a longer life expectancy than other types of flat roofing. They Consist of a single ply of either rubber or plastic formulations that are very durable. The seams of the material are heat welded together forming a watertight bond. Another advantage of TPO membrane or single-ply roofs is that they are very energy efficient. With an assortment of colors to choose from those with more reflective qualities will repel heat and save on energy costs.

In an effort to find a lighter alternative to built-up roofing, modified bitumen roofing or (MBR) was developed in the early “60’s”. Installing a modified bitumen roof comes without a lot of the mess associated with installing built-up roofing. These roofs consist of a flexible asphalt like material with a mineral top coating that is in rolled sheet form roughly 3 feet wide and up to 36 feet in length. These are installed over a base sheet membrane material that provides insulation and helps prevent leaking. As the sheets are rolled out their backside is heated, a process referred to as torch-down, which melds the material to the base. There are also versions of the rolled sheets that use a peel and stick adhesive to adhere to the base membrane.

Built-up roofing has been in use for many years and prior to the introduction of membrane roofing was the most common type of flat roof. Built-up roofing gets its name from the fact the roof consists of many layers. The bottom layer can consist of one or more layers of insulation board which helps provide support to the remaining layers. Multiple layers of tar or asphalt are then placed on the insulation board, alternating with layers of roofing felt. These layers are then topped off with a layer of gravel. The result is a thick, strong roof that is ideal for commercial usage but rarely used in residential construction.