Understanding the Differences Between Low-slope Roof Membranes

Any roof that is nearly flat is called a low-slope roof. This means it has a slope of less than 3 in 12, which means that for every horizontal foot, the roof level rises by 3 inches. They are commonly found on warehouses and commercial buildings that don’t have or need any attic space.

Unlike pitched roofs that use gravity to remove water, a flat roof requires a waterproof surface to protect the roof decking underneath from getting saturated with moisture that would damage the roof structure. The modern solution is to install sheets of impermeable membranes to protect all roof surfaces.

These membranes need to be tough to withstand pools of standing water, heavy wind, freezing and thawing cycles, UV radiation from the sun, expansion and contraction and still remain watertight. It is important that these membranes are installed correctly so that there are no weak spots or seams that can let in moisture.

EPDM Roof Membranes

Ethylene Propylene Diene Monomer is a single-ply rubber-based membrane that has been around for more than four decades. Its main benefits are its resistance to wind and hail and other damaging impacts, making EPDM roofs a popular choice in areas that get a lot of rain. They are mechanically attached and can last from 20 to 25 years with proper maintenance. An issue with this material is it is only available in black, which means it retains heat from sunlight.

TPO Roof Membranes

Thermoplastic Olefin roofing membranes were designed to be energy efficient and effective protection, without the drawbacks of EPDM and other roof membrane systems. This system is also single ply and is chemically installed in sheets. It is available mostly in white but can come in grey or even customized colors. TPO is economical, durable, UV resistant, and easy to install. It’s not known how long TPO will last, as the material is relatively new and has only been installed on buildings in the last 20 years. Also, TPO tends to weather quicker when exposed to high heat for prolonged periods of time.

Built-up Roof Systems

Traditionally, this was done by tar and gravel built-up roofing systems that combined layers of asphalt and coatings to provide protection, but these systems tend to be heavy and are costly to install and maintain. Surfacings of a built-up roof usually include aggregate, which is gravel or mineral granules, aluminum coatings, or hot asphalt. This tends to add a lot of weight to the roof, which means there needs to be adequate roofing structure underneath.

The Frederic Roofing Advantage

We have serviced and installed low slope and flat roofs in the St. Louis area for a very long time. Put our expertise and experience to the test. If you have a hole in your low slope roof or if you need a whole new roof, call Frederic Roofing.

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