A Look at Membrane System Roofs

Membrane roofing systems have been a common choice for commercial buildings for many years. Today, the systems are being used more often for residential buildings and private homes.

The original application was to replace asphalt roofs that were inherently problematic. The asphalt was heavier. Roof leaks were harder to find. Pieces of the asphalt became dislodged easily. The dislodged pieces clogged gutters and caused other problems.

Possibly the biggest disadvantage of the asphalt systems was heat. The presence of “heat islands” in urban communities was noticed several decades ago. The temperatures within the urban communities were sometimes 10 degrees hotter than the suburbs. It was determined that black asphalt roofs were among the main causes of these heat islands.

While all membrane systems are lighter in weight and generally more effective than asphalt, not all of them address the heat island issue. In order for the roofs to be cooler and more energy efficient in the summertime, the system needs to include a white coating as the outermost layer or reflective metallic particles in the outer layers.

The reflective metallic particles have increased the popularity of the “cool roofs”. The particles make it possible for homeowners and commercial building owners to choose colors that may be more aesthetically pleasing than white.

Built-up and modified bitumen roofing systems were the first membrane systems to be seen on the market. They are usually less expensive than some of the more modern polymer choices.

It is called “built-up” roofing because several layers of material are installed. This was to differentiate the system from single layer tar paper and other thin short-lived systems. The number of plies included in a built-up system can range from two to five. In some areas, additional layers are recommended to address common weather issues.

TPO, EPDM, PIB, PVC and CSPE are among the polymer resins that have found use in roofing applications. These are inherently more water resistant but are typically more expensive.

A TPO roofing system consists of plastic sheets welded together using hot air. When installed correctly, this eventually results in a single sheet of water-resistant plastic covering the roof. There are typically three layers included in the TPO membrane system including a polyester reinforced plastic center and a tough TPO compounded top ply.

EPDM is a type of rubber. EPDM roofing has become the standard for RVs, trailers, mobile homes and residences that were traditionally covered with metal. It is one of the most durable systems available.

That was a brief look at membrane roof systems. An experienced roofer can tell your more about your roofing options.