Ballasted EPDM Roof Has Been in Service Since 1979

Rob Nelson is a 44-year-old software consultant who owns a multi-tenant, 137,000-square-foot building in Kingston, Pa. Rob’s dad bought the building in 1985, when it was an abandoned cigar factory and Rob took over management of it in 2002. He considers it to have been a good investment for many reasons. It has attracted a variety of tenants and currently houses about 25 businesses, including small, single-office enterprises, an engineering firm and a home-health nursing business. Rob’s family operates a furniture business and an indoor self-storage facility in the building, as well.

Roof Consultant Mark Sobeck inspects a 35-year-old ballasted EPDM roof on a multi-tenant building in Kingston, Pa.

Roof Consultant Mark Sobeck inspects a 35-year-old ballasted EPDM roof on a multi-tenant building in Kingston, Pa.

Besides its track record of attracting tenants, Rob also values his building for another very important reason: its ballasted EPDM roof has been in place since 1979. If you do the math, that’s 35 years. And Rob’s roofing consultant, Mark Sobeck, based in Wilkes-Barre, Pa., says he can realistically expect his building to get another 10 or 15 years of protection from the roof.

Rob and Mark emphasize that maintenance has been important to the roofing system as a whole. One-third of the original roof has been replaced for reasons not related to the membrane performance, and the flashing and expansion joints have been replaced on the original section of the roof. But the membrane itself, according to Sobeck, is still in great shape. “It’s amazing how the EPDM rubber is still lasting. At thirty-five years, it’s still stretchy and pliable and looks good.”

Nelson’s experience with the longevity of his roof is backed up by in-depth testing by the EPDM Roofing Association (ERA). ERA commissioned studies of five EPDM roofs that had been in use for between 28 and 32 years. The roofs, ballasted and fully-adhered, were first inspected in the field, and then small samples of the EPDM membrane were sent to Momentum Technologies, a testing facility for the roofing industry in Uniontown, Ohio. Five key performance characteristics of the samples were tested: elongation, tensile strength, cross-direction thickness, machine-direction thickness and factory-seam strength. The lab results showed that all the samples had physical characteristic properties above or just below the minimum physical characteristics of a newly manufactured 45-mil EPDM membrane. Put another way, after three decades of use, they were performing like new. Roofing experts point out that installation materials and methods have advanced considerably in the last 30 years, giving new roofing systems an expectation of an even longer service life.

A roof that lasts a long time will deliver obvious financial savings to building owners. In an era when environmental benefits must also be considered, experts say that its important to look at sustainability in the broadest possible terms. “If a roof lasts a very long time,” says John Geary, director of Education and Industry Relations for Firestone Building Products and chairman of the board of ERA, “that’s very good news for the environment. Compared to a roof that has to be replaced every 10 years or so, the choice of EPDM means fewer resources are ultimately used in the manufacturing and maintenance of the roofing system. Additionally, EPDM can be recycled, so it also means less materials winds up in a landfill.”

Rob Nelson may not have seen the results of EPDM lab tests, but he sees proof of the durability and longevity of EPDM every time he visits his building. “It’s pretty wild and definitely surprising that we are still kicking along after 35 years,” he says. Given consultant Mark Sobeck’s projections, Nelson can expect another 15 years or so of “wild” service from his EPDM roof.

Comments

  1. Thank you for your comments. All roof systems are subject to abuse by other trades during construction and require ongoing maintenance to ensure maximum service life. While it is true that small debris can be hidden, stone ballast has proven to be an effective form to secure the membrane in place on billions of square feet of roofs for over 3 decades. In addition stone ballast is excellent protection from hail. To learn more about the durability of EPDM, you can consult our website at http://www.epdmroofs.org.
    Ellen Thorp
    Associate Executive Director
    EPDM Roofing Association

  2. Douglas Cohen says:

    I have not specified a stone ballasted roof in over 20 years due to a lack of confidence in proper installation, a not so strict adherence to manufacturer recommendations, in adequate protection during construction and in anticipation of a general lack of maintenance by Owners. The following is a summary of reasons why I do not specify this type of roof anymore:
    1. Rooftop wind conditions require regular maintenance to make sure ballast is evenly re-distributed over time
    2. Hurricane/Tornado/Heavy storm wind conditions does turn ballast into a projectiles
    3. During Construction, the ballast hides debris and waste left by other trades (I would typically fill two coat pockets with metal strips, nails, screws etc. in just one square on several projects – excluding other types of observed organic and inorganic waste)
    4. Normal construction and post-construction traffic by other trades and maintenance across the roof can cause hidden debris to easily puncture 45 or even 60 mil EPDM, thereby requiring removal of ballast to find the offending leaks. I do acknowledge that reinforced 60 mil EPDM does reduce puncture vulnurability.
    5. If not regularly maintained, wind-blow soil and seed has been observed to create opportunities for weed growth on roofs.

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