EPDM Continues To Perform

EPDM (ethylene propylene diene terpolymer) rubber roofing membrane has been an appealing choice of the low-slope commercial roofing industry for over 40 years, with more than 500,000 warranted roof installations using over 20 billion square feet. Annually, EPDM accounts for over one billion square feet of new roof covering, and is the most frequently used roofing material in the marketplace.

Physical Properties
EPDM is an elastomeric polymer synthesized from ethylene, propylene and a small amount of diene monomer, compounded with carbon black, processing oils and various cross-linking and stabilizing agents. As a thermoset membrane that recaptures its shape after stretching, EPDM maintains its physical properties for decades. EPDM is manufactured in large sheets varying in width from 10 to 50 feet, and features lengths up to 200 feet. The membrane can be reinforced and comes in thicknesses of 45, 60, 75 and 90 mils (thousandths of an inch).

Superior Performance
The greatest test of any construction material is how it performs under actual field conditions. Forty years of empirical experience in field applications has shown EPDM to have the roofing industry’s longest average service life. Characteristics that contribute to this superior overall system performance include:

• Cyclical membrane fatigue resistance;
• Proven hail resistance;
• High resistance to ozone, weathering and abrasion;
• Flexibility in low temperatures;
• Superior resistance to extreme heat and fire;
• Thermal shock durability;
• Ultraviolet radiation resistance.

EPDM’s high resistance to wind damage has also proven to be an increasingly desirable attribute. These roof systems can be designed to meet a variety of wind uplift criteria from Factory Mutual, including 1-60, 1-90 and 1-120 ratings and greater.

Architects, roof consultants and contractors have come to depend on EPDM’s time tested, long-term performance.

Applicability and Ease of Installation
EPDM’s application methods (ballasted, fully-adhered and mechanically-attached) allow the membrane to be installed on slopes with positive drainage up to and including vertical applications for fully-adhered systems. Good roofing practice always includes provisions for proper drainage for any type of roof system and, in most cases, is dictated by local building codes. Because EPDM remains stable over a wide range of temperatures, it allows for year-round installation in all climates.

Many roofing contractors have crews with extensive experience installing EPDM. In an effort to ease installation, EPDM manufacturers continue to implement ergonomic solutions, such as the creation of adhesive application equipment.

Repair and Restoration
One of the unique attributes of EPDM is its ability to be easily repaired and restored – an attribute never seen before in the roofing industry. Even after years of in-field service and exposure to the elements, repairs or modifications involving the installation of a new roof curb into an aged roof can be accomplished easily, with the expectation of long-term performance.

Unlike other roof systems that may degrade and become brittle over time from ultraviolet exposure, EPDM maintains its integrity and flexibility. Because of this, EPDM allows for modifications as easy as washing the membrane, preparing the surface and applying the repair material, including coatings.

Another unique attribute of EPDM is its ability to be restored. Aged and damaged EPDM roof systems are now being restored to original installation quality without major costs or disruption to business. In some situations, when system enhancements are incorporated, the aged roof system is restored to a condition that exceeds that of the original installation.

Environmental Responsiveness
EPDM is one of the most sustainable and environmentally responsible roofing materials used today in the construction industry. Its successful track record of superior overall system performance results in low life cycle costs. Less frequent replacement results in decreased building disruptions and reduced impact on the environment. The initial production of the membrane has a low-embodied energy number (the amount of energy required to produce and implement a product from material extractions, manufacturing and installation).

For designs requiring a coloured surface, an ENERGY STAR® approved coating can be applied. The EPDM surface allows for a robust bond with the coating that results in long-term performance. EPDM also has high emissivity (the percentage of absorbed energy a material can radiate away from itself). This high emissivity allows the heat energy to be reflected back into the atmosphere instead of being absorbed by the building. As a result, a building can “cool off” faster at night, rather than hold the heat.

Low VOC and VOC free products are also available. VOCs (Volatile Organic Compounds) are a factor in creating air pollution.

Numerous manufacturing facilities, locally experienced installation crews and systems that perform well in conditions of high thermal value all allow for Leadership in Energy and Environmental Design (LEED®) point possibilities. In fact, the Green Building Digest’s Issue No. 14 lists EPDM as a “Best Buy” for low-slope roofing. For those systems that have reached the end of their service lives, EPDM membranes are recycled to become walkway pads or used for other purposes.

Unbeatable Economic Value
Although installation costs vary from system to system, and building to building, EPDM roofing systems offer the greatest economic value in the low-slope commercial roofing industry.

Historically, ballasted EPDM has the lowest installed cost per square foot, followed by mechanically-fastened and fully-adhered systems. For more information on EPDM’s unbeatable economic value, contact a local roofing consultant.

Ease of repair and modification contributes to the strong dollar value of EPDM roofs, an attribute that appeals to building owners. This particular attribute cannot be overlooked in these times of business decision accountability measures, and current federal tax regulation that depreciates roofs with life spans exceeding 39 years.

Warranties
Numerous warranty options, from five to 30 years, are available to accommodate almost any budget and building owner requirement. Puncture, high wind and hail coverage are also options, making EPDM an even more appealing roofing membrane. The 30-year warranty options that are now available are based on historical performance, not research projections.

In the past, long-term EPDM membrane warranties required manufacturers to address the issue of EPDM roof systems that were exceeding their warranty period. EPDM roof systems that exceed their warranty period can now have the warranty period extended. The warranty extension programs involve inspection of the roof and the completion of recommended repairs, maintenance and/or system enhancements.

Conclusion
EPDM continues to be the roof system of choice for architects, engineers, roof consultants, contractors and building owners. EPDM offers versatility, product varieties and availability, environmental benefits, contractor knowledge and familiarity, and cost effectiveness. In short, EPDM’s popularity is growing because “EPDM Continues to Perform.” From the arctic reaches of the north to the humid climates of Central America, from the deserts of the Middle East to the continuous wet seasons of the Pacific coast, EPDM’s performance is living proof that quality roof system design and installation continue to stand the test of time.

EPDM Roofing Association
The EPDM Roofing Association (ERA) is a trade association solely representing the manufacturers of EPDM single-ply roofing products and their leading suppliers. ERA provides technical and research support to the public and the construction industry, and communicates the longstanding attributes, consistency and the value proposition of EPDM rubber membrane roofing materials. ERA can be contacted at (703) 684-5020, Fax: (703) 684-6048 or visit the organization’s web site at www.epdmroofs.org.

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