Posts Tagged ‘EPDM Single – Ply Roofing System’

EPDM Roofing Systems Are An Energy Efficient Option

December 16, 2010

Commercial EPDM Single – Ply Roofing System Part 2

EPDM roofing membrane accounts for more than 1 billion square feet of new roof coverings in the United States each year. Today, there are well over 500,000 warranted roof installations totaling more than 20 billion square feet of EPDM membrane in place nationwide.

However, when seeking a “cool roofing” option, many building professionals do not realize that black EPDM provides similar energy savings as its white, non-EPDM, counterparts. A cool roof, as defined by the California Energy Code, is a roof covering or surface that has been tested and labeled by the Cool Roof Rating Council as having an initial solar reflectance of a least 0.70 and an initial thermal emittance of at least 0.75. So where exactly does ballasted roofing fit among cool roofing options?

A three-year study initiated by the Single Ply Roofing Industry (SPRI) and conducted by the U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) was completed in 2008 and provided extensive analysis of the energy performance of ballasted systems. As part of the study, titled Evaluating the Energy Performance of Ballasted Roof Systems, six roof panels – four ballasted EPDM featuring different stone/paver ballast weights and two control panels (a white TPO and a black EPDM membrane) – were subjected to daily weather cycles side-by-side from March 2004 through April 2006.

EPDM Roof System


Among the key findings:

  • The cooling loads for the heavy and medium stone-ballasted and uncoated paver-ballasted systems were approximately the same as for the white system.
  • Cooling loads for the lightweight stone systems were slightly larger than for the white system but significantly less than for the black system.
  • By the start of the second year of the project, temperature and cooling loads increased for the white system due to the effects of weathering.
  • Heating loads for the ballasted systems showed random variation as loading increased and type changed. Except for the heavyweight stone system, they were about the same as for the white system.
  • The heavyweight stone system showed slightly less heating load than the black system but this is considered an anomaly due to rain effects.
  • All evidence on clear days of diurnal behavior showed the heavyweight stone and uncoated paver systems performing equally due to the same thermal mass despite different solar reflectance.

The study further revealed that the ballasted EPDM profiles offered better thermal emittance properties. While solar reflectance measures how well a roofing material reflects sunlight, emittance measures the roofing material’s ability to release absorbed heat back into the atmosphere, rather than into the building. Both are important properties that help a roofing system remain cool.

In the study, the ballasted EPDM profiles delayed the temperature rise for up to three hours, effectively moving about 20 percent of the cooling load into off-peak hours of the day when energy costs are lowest. Summarizing the study’s results, AndrŽ Desjarlais, program manager of the Building Envelopes Program at ORNL, stated that certain ballasted roof systems “are as effective as white-membrane roofs in mitigating peak energy demand.”

As a result, several regulatory bodies across the country have adopted new standards in regard to cool roof materials. For instance, the California Energy Commission has approved the use of ballasted roof systems as a cool roofing option as part of its 2009 Title 24 energy standards. And, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has tentatively decided to update its cool roofing standards and will recognize ballasted roof systems as an acceptable alternative to light-colored materials. Likewise, the city of Chicago, which has earned international accolades for its commitment to sustainable roofing practices, has added ballasted EPDM as an accepted cool roofing alternative in its municipal code for low-sloped roofs.

Talk to a Minnesota commercial roofing contractor to find out if an EPDM roof system is the right choice for your building.


EPDM Roofing Systems Are An Energy Efficient Option

December 14, 2010

Commercial EPDM Single – Ply Roofing System – Part 1

Learn about the energy efficiency, durability and other various benefits of both black and white EPDM roofing systems.

As the green building movement continues to grow with the commercial construction market, energy-efficient roofing technologies are often at the forefront. For many building and roofing professionals, however, much of the attention has been directed solely at white or light-colored reflective roofing materials.

Many roof designers are taking their clues from studies that show reflective roof surfaces reflect solar radiation back into the atmosphere, keeping the roof system cooler and ultimately reducing building energy usage through lower air conditioning demand. In some cases, a white thermoplastic polyolefin (TPO) membrane fully adhered over polyiso insulation may in fact be the most appropriate roof design for a given building. This is especially true in climates where cooling degree days outnumber heating degree days.

Yet, frequently missing from the discussion about creating eco-friendly roofs are several important aspects:

  • EPDM roof systems, both black and white, can provide a strong, energy-efficient option
  • Reducing a building’s heating costs is often more important in many parts of the country
  • The roofing material’s durability and life-cycle assessment should be considered

EPDM Proven History

According to EPDM Roofing Association, ethylene propylene diene terpolymer (EPDM) rubber roofing membrane accounts for more than 1 billion square feet of new roof coverings in the United States each year. Although EPDM has been in use for over four decades, it has been the last 25 years where its growth has made it the single-ply market leader. Today, there are well over 5000,000 warranted roof installations totaling more than 20 billion square feet of EPDM membrane in place nationwide.

Behind more than four decades of successful field performance, EPDM has become the trusted system of choice for many roofing contractors and building owners worldwide. In addition to outstanding weathering characteristics, flexibility, durability, and life-cycle costs, EPDM also offers superior wind, hail and fire resistance. Specifically, ballasted EPDM roofing systems are among the most common and economical installation available today.

Talk to a Minnesota commercial roofing contractor to find out if an EPDM roof system is the right choice for your building.


EPDM Single – Ply Roofing Systems Part 1

July 8, 2010

EPDM Single – Ply Roofing System

EPDM: Ethylene Propylene Diene Monomer (or Terpolymer which is simply a product consisting of three distinct monomers).  EPDM is classified as a Thermoset material which means it is either fully-cured prior to being installed or that it cures during natural weathering after installation.  EPDM roofs are single-ply membranes meaning there is only one ply of roofing material, not multiple plies laminated together.

EPDM has been in use on roofs in the USA since the 1960’s and is one of the most common types of low-slope roofing materials.  This is because it is relatively inexpensive, simple to install, and fairly clean to work with when compared to conventional built-up roofs.  There aren’t the odors and fumes that accompany built-up roofs which appeals to many property owners and managers.

EPDM is a rubber material whose principal components consist of the compounds ethylene and propylene.  A flexible rubber matrix forms when a small amount of diene is added to the mix.  EPDM is available reinforced or unreinforced with both commonly used; it’s also available in either a cured (vulcanized) or uncured (non-vulcanized) state. Vulcanized EPDM is the most common with non-vulcanized often used for flashing purposes.

EPDM membrane thickness ranges from thirty mils (0.030″) to one-hundred mils (0.100″) with the most common thicknesses being forty-five mils (0.045″) and sixty mils (0.060″).  There are three standard application procedures:
(1) fully-adhered
(2) mechanically-fastened
(3) loose-laid

Fully-adhered EPDM uses water or solvent-based adhesives to adhere the rubber to the substrate.  Mechanically-fastened EPDM is attached by manufacturer-approved mechanical means to the substrate, and loose-laid membranes are secured only at the perimeters and any penetrations.  A ballast of round river rock or concrete pavers is used to hold the materials in place.  River rock is usually installed at a rate of 1000 – 1200 pounds per roof square (100 square feet) and the pavers generally weigh approximately 20 pounds per square foot.  Structural integrity is important with loose-laid roof systems.  The seams of all systems are then sealed using either an adhesive or a splice tape.  Splice tapes have tested with a higher tear-strength.