When Insurers’ Own Science Shows Small Hail Can Wreck Roofs

The Insurance Institute for Business & Home Safety (IBHS) has released research that undercuts one of the most common arguments made in hail damage disputes. For years, insurers have insisted that only large, “severe” hailstones can harm asphalt shingle roofs, dismissing smaller storms as inconsequential. Yet IBHS’s own 10-year asphalt shingle study tells a very different story.

The findings, highlighted in a recent presentation slide, show that high concentrations of sub-severe hailstones can dramatically accelerate the aging of asphalt shingles. Researchers at the IBHS Research Center in South Carolina subjected new shingles to repeated barrages of small hail, then exposed them to weathering to mimic real-world conditions. Just two years into this process, the test shingles performed more like those a decade old. The study also revealed that shingles already worn by natural elements were roughly ten times more vulnerable to damage from subsequent small hail impacts than fresh material.

These results confirm what policyholders, roofers, and public adjusters have long observed after “minor” hail events: Shingles can lose granules, develop cracks, and suffer latent weakening even when the hailstones are far below the size typically classified as severe. It is the frequency and concentration of impacts, combined with the relentless march of sunlight, heat, and moisture, that compromise the integrity of a roof.

For insurers, this research should be a wake-up call. The same organizations funding cutting-edge labs to better understand building performance are sometimes slow to translate that knowledge into fair claims practices. Denying damage after a storm simply because the hail report lists stones under one inch ignores the science produced by their own industry. Small hailstorms with extensive strikes, especially when they strike aging roofs or occur repeatedly, can shorten the life of shingles and leave homeowners with real, measurable losses.

Acknowledging these findings would bring much-needed consistency between underwriting, risk modeling, and claims handling. Insurers use IBHS data to price policies, promote the FORTIFIED standards, and advise consumers on how to protect their property.

That same respect for the research ought to extend to the claim stage, where homeowners deserve a good-faith evaluation informed by the latest building science. Until carriers reconcile their field positions with the evidence emerging from IBHS laboratories, disputes over so-called “cosmetic” hail damage will persist, leaving customers to wonder why science stops at the point of loss.

I will post the full study when it comes out shortly in a scientific journal. Until then, you can read the summary at this link.

Thought For The Day 

“As we’ve learned more about hailstorms, we’ve discovered storms that produce large concentrations of small hail are more common than we thought, and despite causing less individual damage than a single large hailstone, small hail, especially in high concentrations, is likely a meaningful contributor to the loss we see each year from hail.”
—Brenna Meisenzahl