FAQs

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.

ARE EPDM MEMBRANE ROOFING ASSEMBLIES FIRE RETARDANT?

An EPDM roofing assembly can be designed to meet Underwriters Laboratories (UL) and Factory Mutual (FM) fire classifications. Like in many other roofing assemblies, the fire retardancy level will depend on roof slope and the various components utilized. Current UL and FM publications contain numerous listings of various approved assemblies.

WHAT ARE THE AVAILABLE THICKNESSES AND TYPES OF EPDM SINGLE-PLY MEMBRANE?

EPDM membrane is manufactured in various thicknesses (.045″ to .090″ thick) and is available as a non-reinforced or reinforced sheet (depending upon application). Other thicknesses are also available for use in non-roofing applications as a special order.

Reinforced membranes contain an internal fabric that is completely encapsulated within the EPDM membrane sheet and is available in various thicknesses (.045″ to .075″). Occasionally, a fleece layer can be added to the underside of the sheet that serves as a built-in underlayment for direct re-roof applications over certain types of existing roofing material.

EPDM is also manufactured as vulcanized (cured) or non-vulcanized (uncured) membrane. Vulcanized membranes have set physical properties due to the vulcanization process and exhibit consistent behavior throughout the sheet that allow the membrane to have memory – this means when the membrane is stretched, it will return to its original state. On the other hand, non-vulcanized EPDM does not have set physical properties because it is not cured when manufactured. This makes the uncured material ideal for use as flashing where the material can be stretched, formed, and shaped.

WHAT MAKES EPDM MEMBRANE SUITABLE FOR NON-EXPOSED ASSEMBLIES (I.E, PROTECTED MEMBRANE APPLICATIONS AND DOUBLE SLAB INSTALLATIONS)?

Structural deflection, improper drain placement, or an insufficient number of drains can result in low areas on the roof that allow moisture to collect and pond over a period of time. Therefore, one of the most important characteristics of a roofing membrane is its moisture resistance. EPDM has excellent moisture absorption resistance that makes the material more tolerable to entrapped moisture than most roofing membranes. Since the early 60s, the material has been successfully used in canals, pond lining and other irrigation systems before its debut as a roofing membrane.

WOULD REPAIRS TO AN EPDM MEMBRANE BE IMPAIRED BY AGING?

No. One of the most unique attributes of EPDM is its ability to be easily repaired as well as its potential for restoration unparalleled in the roofing industry. The characteristics of the membrane are such that, even after years of field service and exposure to the elements, repairs and/or modifications, such as the installation of a new rooftop unit, can be accomplished with ease and with the expectation of long-term performance.

Unlike other roofing systems that degrade or become brittle over time due to UV exposure, EPDM single-ply membrane maintains its integrity and flexibility. This allows for modifications as easy as washing the membrane, preparing the roofing membrane surface, adhesive applications, and the installation of new material.

HOW POPULAR IS EPDM SINGLE-PLY MEMBRANE?

Within the United States, EPDM accounts for over 1 billion square feet of new roofing annually and represents approximately 35% of the entire roofing market. In Europe the market share is around 12% and growing. While it is difficult to predict percentages in other markets, accelerated growth is reported in the Middle East and China as well.

Within the United States, EPDM accounts for over 1 billion square feet of new roofing annually and represents approximately 35% of the entire roofing market. In Europe the market share is around 12% and growing. While it is difficult to predict percentages in other markets, accelerated growth is reported in the Middle East and China as well.

HOW LONG CAN AN EPDM ROOFING SYSTEM BE WARRANTED?

Generally speaking, system warranties that cover material and labor costs are available; and different manufacturers offer various assemblies with standard warranties that vary from 5 and 10 to 15 and 20 years. In addition, premium coverage up to 30 years is available and can include coverage for higher wind speeds, incidental puncture, and hail resistance.