DO I HAVE TO WORRY ABOUT STAIN HARDENING AND POTENTIAL DETERIORATION IN THE FUTURE WHEN A HAIL STORM COMES IN CONTACT WITH MY EPDM ROOF?

Neither manufacture of EPDM has seen evidence of strain hardening in EPDM membrane at anytime in there life.

WHAT CAN I PUT ON SNOW AND ICE TO FACILITATE MELTING AND ONE EFFECT THE EPDM OR MY WARRANTY?

Calcium Chloride will work in most conditions. It can either be spread over the area of concern or placed in a nylon stocking and placed along/around the areas in need of melting. While the Calcium Chloride will not harm the EPDM caution should be taken in regards to where the melt water run will drain, and verification that it will not affect the materials and or vegetation it comes in contact should be obtained prior to placing the Calcium Chloride on the roof.

ARE THERE STANDARD DETAILS FOR USE WITH EPDM SYSTEMS?

Yes. The National Roofing Contractors Association (NRCA) and the Single-Ply Roofing Association (SPRI) publish standard details. However, manufacturers may have modified versions of these details which may not exactly match.

IS THERE AN ASTM STANDARD FOR EPDM MEMBRANE?

Yes, ASTM D 4637.

HAVE THE ASTM STANDARDS FOR LINEAR DIMENSIONAL STABILITY (FOR EPDM) BEEN MODIFIED?

The ASTM standard for linear dimensional stability (ASTM D 1204) was originally 2% maximum. In the mid-90s the standard was changed to 1% maximum. The change in the ASTM standard was influenced by the belief that membrane shrinkage may be a contributor to the bridging seen on some old ballasted applications. In reality, EPDM has always exhibited a dimensional stability value of much less than 1%, even when the ASTM Standard was 2%.

WHAT IS THE CAUSE OF BRIDGING THAT HAS BEEN SEEN IN THE PAST AT ANGLE CHANGES IN SOME EPDM LOOSE-LAID APPLICATIONS?

Some membrane bridging has been observed in the past in some loose-laid ballasted membrane assemblies. The bridging was not seen in adhered or mechanically-fastened applications where the membrane is adhered or secured in place. The cause of this bridging relates to membrane movement experienced in ballasted roofing systems and insufficient securement in the angle change at the base of parapets. This phenomenon was not seen in every ballasted loose-laid assembly but only some (mostly in colder regions) where improper securement is present. Examples include:

Roofing nails used to anchor the roofing membrane to a horizontal wood nailer
Improperly anchored beveled wood nailers fastened to the vertical wall (warping and buckling of the wood occurred)
Rubber nailing strips fastened horizontally or vertically
In 1987, the method of securement was changed to incorporate 2″ diameter plates and threaded fasteners spaced at 12″ on center or a reinforced strip (glued to the underside of the roofing membrane at the angle change) to anchor the roofing membrane. This change in securement method eliminated the bridging. Both NRCA and SPRI have endorsed this securement.

HOW DOES EPDM PERFORM IN EXPANSION AND CONTRACTION SITUATIONS? SHOULD RELIEF OR CONTROL JOINTS BE UTILIZED THE SAME AS ON A BUILT-UP ROOF?

Relief or control joints are commonly used with built-up roofs to subdivide a larger roof area and segregate possible damage into one small area. EPDM, due to its flexibility (-49 F) and elongation, will accommodate stresses caused by temperature extremes, structural movement, and deflection. In cases where the building is designed with expansion joints, the design should be carried all the way through to the roof and an expansion joint should be incorporated into the roof design.

DOES HAIL AFFECT THE PHYSICAL CHARACTERISTICS OF EPDM?

EPDM passes the Factory Mutual (FM) 4470 testing procedure that includes hail resistance, and does not show fatigue from the impact the membrane must endure during a hailstorm. Hail warranties are available and offer protection against 1 inch and 2 inch diameter hail.

DOES PONDED WATER HAVE ANY AFFECTS ON THE PERFORMANCE OF EPDM MEMBRANE?

Since its infancy, when EPDM was used primarily for pond lining and canals, it has demonstrated excellent resistance to moisture absorption. This characteristic made the membrane a candidate for many underground waterproofing applications where the material was buried in saturated soil. (EPDM meets ASTM D 3083 “Resistance to Soil Burial for Underground Application.”)

Moisture found in ponding areas has caused decay of organic felts (built-up roofs), algae growth (light colored roofs), granule loss (modified bitumen roofs), and premature curing and surface cracking (non-vulcanized thermoplastic membranes). This moisture has absolutely no affect on EPDM membrane.

While it is always good roofing practice to provide positive drainage for any roofing assembly, EPDM membrane offers greater safety margins in the event of deflection and subsequent ponding.

IS EPDM UV RESISTANT?

After more than two decades of field exposure in different climatic conditions, samples collected of EPDM membrane show no evidence of crazing or cracking. As a result of the excellent UV resistance, EPDM membrane can be warranted up to 30 years.