Hail size is one of the primary factors determining whether your roof sustained damage during a storm, but it is not the only factor. Wind speed, hail density, impact angle, roofing material type, and roof age all contribute to whether a given hailstone causes functional damage.
This guide provides a practical reference for understanding hail damage thresholds across common roofing materials, with size comparisons homeowners can relate to.
Hail Size Reference
Pea-sized (0.25 inch): Rarely causes roof damage. May cause minor cosmetic marks on soft metals like aluminum siding or gutters.
Marble-sized (0.50 inch): Generally below the damage threshold for most roofing materials. Can cause cosmetic denting on aluminum gutters and downspouts.
Dime-sized (0.75 inch): Approaching the damage threshold. Can cause granule displacement on aged or weathered asphalt shingles. Newer shingles typically withstand this size without functional damage.
Quarter-sized (1.0 inch): The generally accepted damage threshold for asphalt shingles. At this size, most hailstones carry enough kinetic energy to displace granules, bruise the underlying mat, and cause functional damage — especially on roofs older than 8–10 years. Damage is often invisible from the ground.
Half-dollar-sized (1.25 inch): Damage is likely on all asphalt shingle types regardless of age. Granule loss becomes more significant, and mat fracture is common. At this size, damage to wood shakes, some tile products, and older slate also becomes probable.
Golf-ball-sized (1.75 inch): Significant damage is almost certain on any roofing material. At this size, individual impact points are sometimes visible from the ground as dark spots or circular marks. Metal roofing shows clear dents. Tile and slate may crack or puncture.
Tennis-ball-sized (2.5 inch) and larger: Catastrophic damage. At this size, hailstones can puncture roofing materials entirely, crack decking, and cause structural damage. Multiple roofing layers may be compromised.
Why Size Alone Doesn’t Tell the Whole Story
Two storms with identical hail sizes can produce dramatically different damage levels. The variables that matter beyond size include wind speed (hail driven by 60mph winds impacts with far more force than hail falling in calm conditions), hail density (dense, solid hailstones cause more damage than spongy, layered stones of the same size), impact angle (wind-driven hail strikes at an angle, concentrating damage on wind-facing slopes), material condition (a 20-year-old roof sustains more damage from 1-inch hail than a 3-year-old roof from 1.5-inch hail), and impact class rating (some shingles carry Class 4 impact resistance ratings from UL 2218 testing, meaning they can withstand 2-inch steel ball impacts — significantly more resistant than standard shingles).
What to Do After a Hailstorm
If your area experienced hail of 1 inch or larger, schedule a professional inspection regardless of whether you can see damage from the ground. The most consequential damage — granule displacement and mat fracture — is invisible without close-up, hands-on examination.
If hail was smaller than 1 inch but your roof is older than 15 years, inspection is still warranted. Aged materials have reduced impact resistance and may sustain damage from hail that newer materials would withstand.
Document ground-level evidence immediately after the storm: photograph any dented gutters, marked siding, damaged outdoor equipment, or vehicle damage. These conditions correlate with roof-level impacts and support your inspection findings.