Best Practices from the Heart of Hail Alley
Texas roofers know a thing or two about hail.
“All of Central and North Texas gets annihilated by hail at least once a year. Sometimes more than that,” said Mike Anderson, general manager and commercial estimator with Clark Roofing in Waco, Texas.
Texas has led the nation in the number of major hail events – with hailstones at least 1 inch in diameter – for the past eight years.1 From 2020 to 2022, there were 1,747 major hail events in the Lone Star State, accounting for 13.6% of the national total.1 And State Farm paid $510 million in hail-related insurance claims to Texas home and auto owners in 2022 alone.2
A Thick, Hail-Resistant Membrane
Clark Roofing’s go-to single-ply membrane is 80-mil Standard TPO.
“It is by far the best roofing system out there in terms of durability and getting hail ratings and FM Global coverage,” Anderson said. “We do a lot of work with municipalities, the State of Texas and the United States military. They want a long-lasting, durable product and are willing to pay a bit more for it.”
He continued, “TPO can handle the Texas heat. PVC plasticizes in hot climates; the membrane breaks down and deteriorates rapidly as the plastics in it leach out. TPO isn’t as susceptible to that, making it much more durable.”
The thicker 80-mil membrane also withstands Texas’ hailstorms, making roofing systems eligible for 20-year system warranties covering hailstones up to 2 inches in diameter.
A Strong, Wrinkle-Free Bond
A wrinkle-free installation is key to maximizing hail resistance, Anderson said.
“The roof needs to be very tight,” he explained. “If there are places where the membrane isn’t touching the substrate, hail has a better chance of puncturing it.”
To prevent wrinkles – and achieve a better-looking roof – Clark Roofing recommends full adhesion.
“We always fully adhere if the building owner has the budget because it looks so nice,” Anderson said. “It’s more expensive and time-consuming than mechanical attachment, but the results are better.”
And when seeking a Severe or Very Severe hail rating, a fully adhered system is the only option. “If a large piece of hail strikes a plate or screw, it can damage the membrane,” Anderson explained. “So, the system is fully adhered, with plates and screws only used on the roof perimeter to meet wind uplift or FM Global requirements.”
Clark Roofing crews use solvent-based adhesives, such as TPO Bonding Adhesive from Mule-Hide Products, to secure the membrane.
“It flashes better and delivers a stronger bond,” Anderson said.
Of course, the roofing membrane, attachment method and adhesive choice are just part of achieving a hail-resistant roofing system. Stay tuned for a future discussion about selecting the right coverboard to protect the membrane and insulation, and the right accessories to create a polished, professional-looking roof.
1 Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service. Accessed from the Insurance Information Institute, https://www.iii.org/fact-statistic/facts-statistics-hail#Property%20hail%20claims, on June 9, 2023.
2 Source: State Farm, Accessed from https://newsroom.statefarm.com/state-farm-reports-increase-in-hail-claim-costs/ on June 9, 2023.
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