What is EPDM Roofing?
As a commercial contractor, you know that not all roofing materials are created equal. Knowing what material to recommend to a client — and being able to explain why you're recommending it — can help your business stand out from the competition.
One type of roofing material that contractors often use is ethylene propylene diene terpolymer, commonly known as EPDM. But what is EPDM roofing? Learn more about this popular material, why you might install it and what types of roofs it is best suited for.
What Is EPDM Roofing?
The EPDM Roofing Association (ERA) describes EPDM as a durable, synthetic rubber roofing membrane. The primary ingredients in EPDM are ethylene and propylene, both of which come from natural gas and oil. Since EPDM is thermoset, it doesn't become soft and pliable when heated.
Usually, EPDM roofing comes in sheets that can measure anywhere from 7.5 feet wide to 50 feet wide. The sheets are usually between 45 and 60 mils (1 mil is equal to 0.001 inch, according to the NRCA), although the ERA notes that a 90-mil thick EPDM roofing material has recently been introduced. The thicker the material, the better it can withstand rain and wind damage.
The most common color for EPDM roofing sheets is black, but white, reflective sheeting is also available. Which color a contractor chooses should depend on the number of cooling degree days and heating degree days in the region. In the Northern states, where there are more cooling days than heating days, black EPDM roofing conserves energy by allowing the snow and ice to melt more quickly from the roof system. In the Southern states, where there are more heating days than cooling days, a white PVC or TPO membrane is a better choice to reflect the sun's heat and conserve energy.
The Benefits of EPDM
Why is EPDM one of the most popular materials among roofing contractors? This material is fairly hardy in the face of roof damage. EPDM can withstand hail, fluctuations in temperature and ultraviolet exposure. It can also put up with prolonged exposure to ozone and abrasion. One key benefit of EPDM for roofers is that large rolls and pre-fab options make it relatively easy to install on low-slope roofs.
There are also some environmental benefits of installing an EPDM roof. The ERA mentions that EPDM roofing has a "low embodied energy number," which means that the amount of energy needed to produce the material and create the roofing sheets is very low. Once EPDM has reached the end of its usable life on a roof, it can easily be recycled and kept out of the landfill.
How Does EPDM Compare to Other Materials?
EPDM is often compared to two other common membranes that can be used on low-slope commercial roofs: Polyvinyl chloride (PVC) and thermoplastic olefin (TPO). All three are around the same price point, according to Roofing Calculator, but differ in installation and resistance to factors like weathering and heat.
Unlike EPDM, both PVC and TPO are thermoplastic, meaning they can be installed with a heat welder. Meanwhile, EPDM seams are sealed with seam tape. Roofing Calculator notes that EPDM sometimes fails in overall durability compared with other membranes, especially if it is installed by a contractor who is inexperienced with the material. No matter which membrane options you offer to your roofing clients, make sure your crews know how to safely and correctly install the membrane itself and accessories such as ventilation.
EPDM's availability in wide rolls makes it suitable for very large, flat roofs on buildings such as warehouses, shopping centers or hotels.
Why learn about EPDM? Knowing the tools and materials of the roofing trade will help you offer clients the best roofing options and the best service possible.