Hail research sets standard for stronger homes

Every year, hail causes billions of dollars in damages to homes, cars, and crops across the United States, according to the National Severe Storms Laboratory with NOAA.

In the Carolinas, the greatest risk for hail comes during our severe weather season of March through July, with a peak in May.

The Insurance Institute for Business and Home Safety has been researching the impacts of hail for more than a decade, trying to simulate hailstorms in their labs so builders can know exactly what they’re up against.

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Ian Giammanco, the lead research meteorologist said it starts with creating the right ice in the right shape. While the lab can’t create a thunderstorm column to create its hail, it simulates this process by freezing ice in a column through refrigerants and injecting CO2, then molding it into spheres.

“It’s less dense than something that you pull out of your freezer so it mimics natural hail,” he said.

Before ice, Giammanco said researchers tried to mimic hail with steel ball bearings.

“It’s very hard, it doesn’t flex, it doesn’t do anything so the surface area where it hits is very small,” he said. “The damage looked nothing like real hail damage at all.”

Most of that damage was limited to dents, but ice can shatter, adding another dimension to its impact on your average roof. The surface area is bigger when it shatters, and that can pull off some protective materials on your typical asphalt shingle.

“What that does is expose the underlying asphalt material to sunlight and that’s ultraviolet, and ultraviolet will make these more brittle,” Giammanco said.

This could weaken your roof before the next storm, so Giammanco said if you can see balding patches on your shingles from the ground, it’s a clear sign you likely have significant hail damage.

“It’s going to shorten the life of that roof,” he said.

Since IBHS started publishing its hail research, Giammanco said he’s been pleasantly surprised by how quickly builders took it to heart.

“We don’t have a poor performing impact-rated shingle anymore,” he said. “The manufacturers have actually raised the bar, that the majority of products fall into our good and excellent category, these are ones that are designed to resist hail.”

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Giammanco said that’s why IBHS is working to expand their research further, by shaping their lab-created hail more closely like naturally occurring hail, or testing their hail cannons on new surfaces like solar arrays.

“If we can make the test representative of real life, that’s just going to raise the bar for the consumers,” he said.

(WATCH > What You Need to Know: Hail