Flat Roofs

ProLine Roofing has extensive experience with commercial and residential flat roofs

Flat roof systems can be complex and require special training and knowledge to install them correctly. There are 4 main flat roof systems being used today. Modified Bitumen, EPDM, TPO, and Built-up systems of hot tar and gravel. Each system has its advantages and disadvantages and choosing the correct system for your specific installation is critical. The professionals at ProLine have nearly 40 years’ experience working with these flat roof systems and can help you choose the right system for your particular installation. 

A brief description of each system, their advantages and disadvantages, and limitations of each system can be found below:

Tar & Gravel – The traditional hot-tar-and-gravel roof is built from three or more plies of waterproof material alternated with hot tar and ballasted by a layer of smooth river stone. Once made of tar paper, these types of roofs gradually are using more-advanced materials such as fiberglass membranes. This system is rarely used anymore because it’s very labor intensive, it’s dangerous and messy to apply, and produces noxious odors during installation.

Modified Bitumen Rubber Roof System (MB) was developed by the Italians in the 1960s and made its way to the U.S. by the late 1970s. The rubber membrane is made of reinforced fabrics covered with asphalt, which consists of modifiers that give the asphalt its elastic properties. The MB roof system is typically installed as a single-ply system; however, it can also be installed in a 2-ply system to extend the roof life to 40 years or more. Some advantages of this roof system are; ease of installation, durability and UV protection. This is a perfect material for a residential flat roof that may have trees overhanging the roof because the membrane is thick and resists punctures. It is also available in several colors to coordinate with shingles. The disadvantages are that the membrane comes in 36” wide rolls and has numerous seams.

Thermoplastic polyolefin (TPO) single-ply roofing membranes are among the fastest growing commercial roofing products and have gained broad industry acceptance for their many performance and installation advantages. As demand increases for heat-reflective and energy efficient roofing systems, TPO single-ply roofing membranes continue to provide exceptional resistance to ultraviolet, ozone and chemical exposure. This product comes in large rolls up to 20’ wide, that minimizes seams in the installation. All seams are heat-welded, so the finished roof has virtually no seams to fail. Since this membrane is white, it is highly reflective, and can safe thousands of dollars on energy bills over the life of the roof. It also qualifies as an Energy Star roofing system.

EPDM – This is a single ply rubber roof system, in which seams are glued or taped together with special adhesives and seam tapes. Think a bicycle inner tube. This membrane is usually black and offers little resistance to UV rays, and is susceptible to puncture and seam failure. The main advantage to this system is that it comes in wide rolls that minimize seams, it has excellent expansion and contraction qualities and is relatively inexpensive. When installed on large commercial applications, it can be covered with a gravel ballast to protect it from UV rays and provide better wind uplift.

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