What Size Hail Damages a Roof?
Hail damage to asphalt shingles typically begins at about 1 inch in diameter – quarter size – on 3-tab shingles, and about 1.25 inches on laminated architectural shingles. Cedar shakes and fiber-cement tile start around 1.5 inches, concrete tile around 1.75, and built-up gravel roofing around 2.5. Those figures come from ice-stone impact testing by Haag Engineering, confirmed against roofs surveyed after real hailstorms.
Hail of a given size does not automatically damage a roof. Those thresholds describe where damage begins across many roofs, not what happened to yours. Impact angle, stone hardness, temperature, roof age and which slope faced the storm all vary. The tool below shows where your situation sits against the measured thresholds, and what to check.
Hail of a given size does not automatically damage a roof – but researchers have measured the sizes at which damage starts for each roofing material. Pick the hail you saw and your roof type to see where you sit against those documented thresholds, and what to check.
Hail Damage Risk
Based on published impact-testing thresholds. This tells you how likely damage is – it cannot tell you whether your roof is damaged.
What this means
What hail this size can affect
What to check – from the ground
Damage thresholds by roofing material
Measured by Haag Engineering using launched ice stones and confirmed against field surveys after real hailstorms. "Threshold" means the size at which damage begins – not the size at which it is certain.
Get the roof looked at properly
Hail damage is often invisible from the ground and still very real – fractured mats and crushed granules that shorten the roof's life without leaking today. We inspect, document what we find with photos, and tell you honestly whether it is worth a claim.
Book a Free Hail Inspection Or read what hail damage on a roof actually looks like.Sources and method
- Damage thresholds are from Marshall, Herzog, Morrison and Smith of Haag Engineering, "Hail Damage Threshold Sizes for Common Roofing Materials", presented to the American Meteorological Society. Their field-observation table gives: 3-tab asphalt 1.00″, 30-year laminated shingles 1.25″, cedar shingles 1.25″, medium cedar shakes 1.50″, fiber-cement tiles 1.50″, concrete tiles 1.75″ and built-up gravel roofing 2.50″.
- Impact energy figures are terminal-velocity and kinetic-energy values for hailstones after Greenfeld (1969), as reproduced in the same paper – for example a 1″ stone falls at about 50 mph carrying under 1 ft-lb, while a 2″ stone falls at about 72 mph carrying roughly 22 ft-lb.
- Hail size names follow the National Weather Service comparison chart. One inch – quarter size – is the severe thunderstorm criterion.
- Impact-resistant shingles are rated under UL 2218 with steel balls of 1.25″ (Class 1), 1.50″ (Class 2), 1.75″ (Class 3) and 2.00″ (Class 4). A Class 4 rating is a laboratory result, not a guarantee of field performance.
- Roof age shifts the effective threshold down, because the Haag testing found aged and thinner products consistently more susceptible than new ones. That adjustment is our own, applied to their published figures – the thresholds themselves are unmodified.
Hail damage threshold sizes by roofing material
From Haag Engineering’s field-observation table, the size at which hail damage begins on each material:
| Roofing material | Damage threshold | Comparable object |
|---|---|---|
| 3-tab asphalt shingles | 1.00 in | Quarter |
| 30-year laminated shingles | 1.25 in | Half dollar |
| Cedar shingles | 1.25 in | Half dollar |
| Medium cedar shakes | 1.50 in | Ping pong ball |
| Fiber-cement tiles | 1.50 in | Ping pong ball |
| Concrete tiles | 1.75 in | Golf ball |
| Built-up gravel roofing | 2.50 in | Tennis ball |
Age matters alongside size. The same testing found that lighter, thinner and older roofing products were consistently the most susceptible, with the lowest damage thresholds. A twelve-year-old laminated roof does not behave like a new one.
Why collateral damage is better evidence than your memory of the hail
People reliably overestimate hail size after the fact, and adjusters know it. What holds up is physical evidence: dented gutters and downspouts, damaged vent caps and turbine housings, torn window screens, flattened AC condenser fins, marked fence caps and – most usefully – dents on a vehicle that was parked outside.
Those are soft targets that record impact energy directly. If they are marked, the hail carried enough energy to matter, whatever anyone remembers about the size of the stones.
What hail damage on a roof actually looks like
The signature of hail on an asphalt roof is not a hole. It is a circular area of granule loss with a bruised, soft spot underneath where the mat has fractured – often invisible from the ground and frequently not leaking at all on the day it happens. That is what makes hail damage genuinely difficult for homeowners to assess: a roof can be materially shortened in life without showing a single symptom you would notice.
On metal, the same impact usually produces a dent rather than a fracture. That is a different problem: functionally the roof keeps working, but the damage is visible, and many carriers now exclude cosmetic damage to metal roofing specifically. Check the policy wording before assuming a dented metal roof is a claim.
Please do not climb up to check
Hail-struck shingles are more fragile than sound ones, and walking on them can create the damage you went up to look for – as well as being the most common way homeowners get hurt on their own property after a storm. Everything worth checking is visible from the ground, an upstairs window, or the attic.
Frequently asked questions
What size hail damages a roof?
Damage to 3-tab asphalt shingles typically begins at about 1 inch – quarter size – and at about 1.25 inches on laminated architectural shingles, according to impact testing by Haag Engineering confirmed against real hailstorm surveys. Cedar shakes and fiber-cement tile start around 1.5 inches, concrete tile around 1.75 inches and built-up gravel roofing around 2.5 inches. These are thresholds where damage begins, not sizes at which it is certain.
Does 1 inch hail damage a roof?
It can. One inch is the National Weather Service severe thunderstorm criterion, and it is the documented threshold at which damage begins on older, thinner 3-tab shingles. On a newer laminated architectural roof, one-inch hail is below the threshold – though not so far below that damage can be ruled out, particularly on a weathered roof or the slope that took the brunt of the storm.
Can hail damage a roof without causing a leak?
Yes, and this is the most important thing to understand about hail. The typical signature is a circular area of granule loss with a fractured mat beneath it. That shortens the roof's remaining life considerably while leaking nothing at all on the day. A roof can be materially damaged and show no symptom a homeowner would ever notice.
How soon should I have my roof inspected after hail?
Sooner rather than later if the hail was at or near the threshold for your material, or if you are seeing collateral damage at ground level. Texas insurance claims carry deadlines, and physical evidence degrades – granules wash away, dents get repaired, and memory of the storm date fades. Documenting it early costs nothing and preserves your options.
Are impact-resistant shingles worth it in Austin?
Class 4 impact-resistant shingles are tested under UL 2218 against a 2-inch steel ball dropped to match the kinetic energy of a hailstone that size. That is a laboratory result on a new product rather than a field guarantee, but it is a real difference – and in Texas, Class 4 products can qualify for an insurance premium discount, which changes the economics.
Does hail damage metal roofs?
Hail dents metal panels at sizes well below what would puncture them, so the damage is usually cosmetic rather than functional – the roof keeps working but does not look the same. Whether that is claimable depends on your policy, as many carriers now exclude cosmetic damage to metal roofing. Functional damage such as split seams or punctured panels generally requires considerably larger hail.