Metal vs asphalt roofing in hail country

Last reviewed 2026-08-11 · How we research and update this · How this site is funded

Two materials, two failure modes

Most comparisons of metal and asphalt are written as durability contests, which is the wrong frame for hail. Both survive most storms. What differs is how they take the hit.

Asphalt fails by losing its surface: a stone strips granules and can fracture the fiberglass mat beneath, shortening service life even though the roof does not leak that night. Metal fails by deforming: a stone dents the panel, and the panel keeps shedding water exactly as before.

Hold that distinction, because the insurance argument follows from it. Damage that shortens service life is easy to call functional. Damage that changes shape without changing performance is what a cosmetic damage exclusion exists to exclude.

Metal under hail: dents, not leaks

Steel and aluminum panels are ductile: hit them hard enough and they deform locally and stay deformed. They lose no protective layer, they do not oxidize faster, and the coating usually survives intact. Barring a coating fracture that exposes bare steel, a dented panel has essentially the same remaining service life as an undented one.

Functional failure from hail on residential metal is uncommon and needs either exceptional stone size or a compromised installation. What does happen: a coating fracture on a sharp deformation, which can start corrosion on steel; loosened fasteners on exposed-fastener systems; damage to ridge caps, trim and pipe flashings, all lighter than the field panels; and seam separation near an impact.

The common outcome is a roof full of dents that works perfectly and looks bad in raking light. Whether that is a covered loss is a policy question.

Gauge, profile and what actually resists denting

Not all metal roofs dent alike, and the differences are large enough to matter at the point of purchase.

Gauge. Steel thickness is described by gauge, where a smaller number is thicker. Residential steel runs commonly in the 29 to 24 gauge range, with 26 and 24 the usual standing seam choices, and a thicker panel resists deformation. Aluminum is specified in decimal thickness and is softer than steel at the same thickness, which is why it dents more readily but is chosen anyway in coastal environments.

Profile geometry. A flat surface has nothing to stiffen it. Ribs and striations increase stiffness and give the eye a texture that breaks up reflections, so a striated panel both resists denting better than a smooth pan of the same gauge and hides the dents it does take. A wide, flat, dark standing seam pan is the most dent-revealing metal roof you can install.

Substrate and surfacing. A panel over solid decking deforms less than one spanning open purlins. And stone-coated steel carries a bonded mineral layer that absorbs impact energy and, like granules on a shingle, disguises minor deformation — the reason it behaves so differently from bare painted steel in the same storm.

Standing seam, exposed fastener and oil canning

Exposed fastener systems screw through the face of the panel with a rubber washer under each head. They are cheaper, faster and universally available. The washers are consumables: they harden and shrink under UV and eventually need re-screwing, a maintenance item measured in years, not decades. Hail can loosen fasteners and damage washers directly.

Standing seam hides the fasteners under the seam, on clips that let the panel expand and contract. Nothing penetrates the water plane in the field of the roof, which removes the most common leak source on metal roofing. It costs substantially more and needs a specialist crew.

Oil canning is the visible waviness in flat areas of metal panels, especially in low sun. It comes from residual stress in the coil, thermal movement and slight substrate irregularities. It is not a defect and does not affect performance, but homeowners who were not warned about it are reliably unhappy. Heavier gauge, striations, narrower pans and tension-leveled coil reduce it.

Asphalt under hail

Asphalt shingles are cheaper, installable by essentially any crew in the country, available within days, and repairable in small areas. They are also the material every property adjuster has been trained on, which makes claims predictable: test squares, per-slope thresholds and depreciation schedules are all well established.

The trade is service life and the granule failure mode. A hailstone knocks granules off, exposing asphalt to UV, and may fracture the mat underneath without tearing it — the classic soft bruise. It does not leak now; it shortens the life of the shingle. How to read that in your gutters is in granule loss.

Impact-resistant shingles are the direct response. UL 2218 rates prepared roof coverings by dropping steel balls of increasing diameter from specified heights, Class 4 being the highest and corresponding to a two-inch ball; a related standard uses launched ice balls instead. Class 4 shingles get there through a more flexible asphalt formulation, a reinforcing scrim on the back, or both. They are not hail-proof — a steel ball in a lab is not a wind-driven stone — but they raise the size at which functional damage begins. See impact-resistant shingles, the impact resistance comparison tool, and what size hail damages a roof.

The middle ground: composite shake and stone-coated steel

Synthetic composite shakes and slates are molded polymer products imitating cedar shake or slate. Many carry a Class 4 rating, because the polymer absorbs an impact and recovers rather than fracturing. They have no granules to lose and conventional crews install them. They cost considerably more than asphalt, the market has fewer manufacturers, and long-term field data on any specific formulation is thinner because the products are newer.

Stone-coated steel is a steel panel or tile with a bonded mineral surface, combining the long life of coated steel with the impact absorption of a mineral layer. The trade-offs are cost, weight relative to asphalt, and a smaller pool of experienced installers.

How insurers treat each, and the trade nobody explains

Class 4 asphalt may earn a premium credit. Many carriers in hail-prone states file a discount for roofs with a UL 2218 Class 4 rating. The credit recurs every year. It is also carrier- and state-specific — there is no national number, and anyone quoting one is guessing. Confirm it in writing before choosing material on that basis, and keep the product documentation.

A metal roof may come with a cosmetic damage exclusion. In many hail-exposed markets, carriers write metal and tile roofs subject to a cosmetic damage endorsement, sometimes as a condition of writing the risk at all. It says, in effect, that damage altering appearance without affecting the roof's ability to keep water out is not covered — which is nearly a definition of hail damage to metal.

So the trade runs like this. Buy the material that almost never fails functionally, and accept that its likeliest storm damage falls in the category your policy is likeliest to exclude. Or buy the material that does fail functionally, and rely on its failure mode being the one insurance pays for.

Cost and service life ranges

Noise, lightning and resale

Noise. Residential metal goes over solid decking with underlayment, usually above an insulated attic, and in that assembly it is not meaningfully louder in rain than any other roof. The reputation comes from agricultural roofs screwed directly to open purlins — a genuinely loud and completely different construction.

Lightning. A metal roof does not attract lightning or increase strike probability. It is non-combustible and conductive, both favorable properties if a strike does occur.

Resale. Metal reads as premium in some markets and unusual in others, and the return is local. What is consistent is that a documented Class 4 roof with an active insurance credit is easier to explain to a buyer than a fifteen-year-old shingle roof of unknown provenance.

How to choose

Standard asphalt if you expect to move within a decade, your budget is tight, or you would rather rely on a well-understood claims process than on the material.

Class 4 asphalt if you are staying, you are in a repeated-hail market, and your carrier confirms an impact-resistant credit — credit plus reduced claim frequency often outruns the upcharge over the life of the roof.

Metal if you are staying long enough to amortize it, you have confirmed how your carrier treats metal on your policy, and you can accept dents you may never be paid to fix. Choose heavier gauge and a striated or ribbed profile.

Stone-coated steel or synthetic composite if you want long life and low cosmetic-claim exposure together, and can find an installer experienced in the system.

Not sure which applies to you? Start with the quiz, or browse the materials section.

Common questions

Sources

Every factual claim on this page that comes from outside our own data is sourced below. Where a number is a model or a range rather than a measurement, it is labelled as one in the text.

• UL Solutions — UL 2218 impact resistance classification of prepared roof covering materials, Class 1 through Class 4
• Insurance Institute for Business and Home Safety — hail research and impact-resistant roofing performance work
• ASTM International — standard specifications for asphalt shingles and for metal roof panel materials and coatings
• NAIC — state insurance departments, where cosmetic damage endorsements and impact-resistant roof credits are filed and published
• Insurance Information Institute — how homeowners premium credits and roof endorsements work

More in costs and materials

• Roofing materials and how they handle hail
• Hail damage vs normal roof wear
• What size hail actually damages a roof
• Impact-resistant shingles and your premium
• Granule loss: the damage you can see from the gutter
• Repair or replace after hail?
• What a roof replacement costs in 2026