What does hail damage look like on a roof?

Hail damage is best measured in a lab, not from the ground: IBHS tests shingles with 1.5- and 2.0-inch steel hailstones and grades three outcomes — dents, tears, and granule loss. There's no official hail size at which roof damage begins; 1 inch is simply the threshold the National Weather Service uses to log a storm as "severe."

Hail damage to a roof is best assessed through lab testing, not a glance from the driveway: IBHS rates shingle performance using 1.5- and 2.0-inch steel hailstones and grades three specific outcomes — dents, tears, and granule loss. There’s no official hail size at which roof damage reliably begins; the 1-inch threshold used in storm reports marks when NOAA classifies a storm as “severe,” not when a roof starts taking damage. Because granule loss — often the most common real-world outcome — can be invisible from ground level, a visual scan alone can’t confirm or rule out hail damage.

What does hail actually do to a roof, according to real impact testing?

IBHS evaluates shingle performance in controlled lab tests using 1.5-inch and 2.0-inch steel hailstones, grading results across three distinct damage modes: dents, tears, and granule loss. Those three categories — not a single pass/fail visual check — are how the industry’s own impact-testing research actually defines hail damage.

Dents are an indentation in the shingle surface; tears and cracks are breaks in the shingle mat itself, similar in kind to what UL 2218’s steel-ball drop test checks for on a shingle’s underside; granule loss is the stripping-away of the protective mineral surface that shields the asphalt layer beneath. A real hailstorm can produce any combination of the three on the same roof, not necessarily all of them at once.

Does hail have to reach a certain size before it can damage a roof?

No official size threshold marks where roof damage begins — IBHS testing explicitly avoids drawing a bright line at any specific hailstone diameter. The 1-inch figure often repeated alongside hail damage is actually the National Weather Service’s severe-thunderstorm reporting criterion, not a damage threshold; those are two different things measuring two different questions.

A storm that never reaches 1 inch of hail — and so never gets logged as “severe” in NOAA’s Storm Events Database — can still strip granules or dent shingles, covered next. Conversely, a storm that does clear the severe-reporting bar doesn’t guarantee every roof beneath it took damage. Conflating the reporting threshold with a damage threshold is exactly the kind of claim IBHS’s own testing doesn’t support.

Can hail damage a roof even when the hail itself is small?

Yes — IBHS research found that sub-severe hail, meaning stones under 1 inch, can still strip away a shingle’s protective granules, exposing the asphalt layer beneath to sun and weathering. That granule loss can leave a roof “up to ten times more susceptible” to damage from a later, larger hailstorm.

That means real damage can already exist on a roof that never saw hail large enough to make NOAA’s severe-storm log — and that damage is largely invisible until a bigger storm exploits the already-thinned granule layer. It’s a good reason not to treat “the last storm wasn’t that bad” as proof a roof escaped unaffected.

Can you tell if a roof has hail damage just by looking at it from the ground?

Not reliably. Granule loss — one of the three damage modes IBHS tests for — is easy to miss from ground level, and a roof can look intact from the driveway while its protective surface has already been thinned by an earlier storm. A closer, professional look is often the only way to know.

This corpus doesn’t support a shingle-by-shingle visual checklist for spotting hail damage from the ground, because that isn’t how the primary research actually evaluates it — IBHS grades damage in a controlled lab setting, not through a homeowner’s naked-eye inspection. A roof inspection or the insurance adjuster’s own visit exists precisely to settle what a ground-level look can’t. See Roof Inspection for what that closer look actually involves.

What should you do if you think your roof has hail damage?

Photograph and video the roof before any cleanup begins, and report the damage to your insurer as soon as possible — the Texas Department of Insurance recommends both steps as the first move after any storm. Don’t throw away any damaged materials until your adjuster has had a chance to see them.

Because so much real hail damage isn’t visible from the ground, documenting the roof thoroughly — even areas that look fine — gives the adjuster and any inspector more to work with than a homeowner’s visual guess. See how to file a roof insurance claim in Texas for the full step-by-step process, and how bad hail actually gets in Cypress and Harris County for the local storm record behind these recommendations.