SpecTips - EPDM Rubber Roofing: Time-Tested and Proven Hail Resistance

EPDM Rubber Roofing: Time-tested and Proven Hail Resistance

With the annual occurrence of major hail storms that affect North America, many building owners are looking to acquire more hail-resistant roofing systems.

EPDM roofing membranes have a great track record of resisting hail damage and keeping water out of buildings, which cancut owners’ financial losses considerably. Non-reinforced rubber’s ability to elongate over 400% is one of the primary reasons EPDM roofing membrane has great hail resistance. EPDM rubber stays flexible throughout its lifecycle,providing good hail resistance even at the end of its warranty term–unlike other materials that tend to get more brittle with age.

Adhered systems with a minimum 60-mil non-reinforced EPDM membrane have been shown to resist up to 3” simulated hail impact without fracture or damage to the membrane,regardless of whether the membrane was new, heat-aged,or field-weathered for 15 years. A report prepared by Jim Koontz and Tom Hutchinson states, “The results of this research clearly indicate that non-reinforced EPDM...offers a high degree of hail resistance...field-and heat-aged EPDM membrane... retains the bulk of its impact resistance as it ages.”

Ric Vitiello of Benchmark Services, another veteran of roofing industry hail research, documented his findings in a 15-page report. He commented, “Based on field and test data, it is clear that EPDM outperforms other roof systems.” In hail-prone locations, it is critical that your project specifications require non-reinforced EPDM membranes that have been tested per UL 2218 and have a Class 4 rating for hail resistance.Include verbiage in Division 7 of MasterFormat specifications in Section 075323 Ethylene-Propylene-Diene-Monomer (EPDM) stating EPDM membrane must have a UL 2218 Class 4 rating.

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