What Are Impact-Resistant Shingles?

What impact-resistant shingles are

An impact-resistant shingle is a shingle that a lab has hit with hard balls and found still whole. The result is a class number. Class 1 is the lowest and Class 4 is the highest ². When a roofer says "Class 4 shingles," this is what they mean.

Most impact-resistant shingles look like ordinary asphalt shingles. The difference is inside. Makers use tougher mats, rubber-modified asphalt or other changes so the shingle bends instead of cracking. The rating belongs to the product, not to the look. Two shingles that look the same can carry different classes.

The rating is not limited to asphalt. UL 2218 is used for many steep-slope coverings, including metal panels and tiles ¹. That is why "hail-resistant roofing" is a wider term. This page uses shingles as the main case and covers the other materials where the tests differ.

How the UL 2218 steel ball test works

In UL 2218, the lab builds a 3-foot by 3-foot sample of new, unweathered roof covering ¹. Then it drops steel balls on it. The ball size sets the class: 1¼ inches for Class 1, 1½ inches for Class 2, 1¾ inches for Class 3 and 2 inches for Class 4 ².

The lab does not just pick random spots. It aims at the places most likely to fail: edges, corners, unsupported areas and joints ².

A sample passes when it takes two hits in the same spot at each of six spots and shows no tearing, fracturing, cracking, splitting, rupture, crazing or other opening ¹. Crazing is a web of fine surface cracks. The lab checks the front, the back and the layers below.

Notice what the test checks. It asks whether the covering opened up. It does not grade dents or lost granules, the little stones on top of an asphalt shingle. Those can still matter to how the roof looks and ages, and to an insurance adjuster.

Read the result as a pass on one lab test of new material, not a promise about how the roof will look after a real storm.

The four UL 2218 classes

Ball sizes from DECRA's summary of UL 2218 ²; pass rule from Professional Roofing ¹.

Every class uses the same pass rule: two hits in one spot, six spots, no opening. A product that fails at one size can be rated at the size below.

FM 4473: the ice ball test for rigid roofing

FM Approvals runs a second test, FM 4473. It is written for rigid roofing such as slate, concrete and clay tiles or planks, not for flexible shingles ³. Instead of steel balls, it fires ice balls from a launcher at the speed of falling hail ³.

The class sizes match UL 2218: a 1¼-inch ice ball for Class 1, 1½ for Class 2, 1¾ for Class 3 and 2 inches for Class 4 ³.

The ice is made from distilled water, frozen for at least 48 hours, and must be free of cracks and bubbles ³.

FM says ice balls are harder and denser than most hailstones, so they stand in for a worst-case stone ³.

FM is open about the limits too. Its standard says long exposure to weather "has a potential to significantly lower the hail resistance of the roof materials," and that it is meant for new materials ³. It also says passing this test alone does not earn FM Approval ³.

Worked example: what a Class 4 label does and does not tell you

An illustrative case using the test rules above ^{1 3}.

So a Class 4 label is a fair way to compare products on the shelf. It is not a promise that hail will never damage your roof.

Where impact-resistant shingles are used

These shingles matter most where hail is common. State Farm, for one, lists 26 states where it offers a discount for certain impact-resistant roofing, from Texas and Oklahoma to Minnesota and Colorado ⁶. That list hints at where insurers see hail risk.

States are also paying attention. The Oklahoma Insurance Department runs grants under the Strengthen Oklahoma Homes Act for roofs that meet FORTIFIED standards set by IBHS, the Insurance Institute for Business and Home Safety ⁸. The department says "many insurance companies offer reduced premiums for homes with such modifications" ⁸.

Outside hail country, an impact-rated roof may still be chosen for falling branches or simply for a tougher shingle. But the insurance case is weaker where there is no credit.

Benefits of impact-resistant shingles

• A tested, comparable rating. Class 1 to 4 lets you compare products on one scale ².
• Possible insurance credit. The Texas Department of Insurance says roofing materials "may be eligible for discounts" and Class 4 "would receive the highest premium credit" ⁴.
• Wide carrier support. State Farm offers a discount for certain impact-resistant products in 26 states ⁶.
• Possible state help. Oklahoma offers grants for qualifying roofs ⁸.
• Same look as standard shingles. Most Class 4 asphalt shingles look like regular architectural shingles.

Limitations of impact-resistant shingles

• New material only. Both tests use new, unweathered samples at room temperature ^{1 3}.
• Real hail is different. Professional Roofing notes hail often falls as temperatures drop fast, which stresses roof surfaces in ways the lab does not ¹.
• Pass or fail only. UL 2218 checks for openings, not dents or granule loss.
• Credits are not promised. Each insurer sets its own amount ⁴.
• Conditions apply. State Farm does not give the credit for a roof laid over an old roof, except some metal roofs ⁶.
• Not all materials count. One insurer's Alabama guideline excludes wood and synthetic polymer ⁷.

What drives the cost of an impact-resistant roof

We do not quote prices. These are the cost drivers. For numbers, try the roof cost calculator.

• Impact class. Class 4 products usually sit above standard shingles in a maker's line.
• Material. Asphalt, metal, composite and tile each carry their own price range.
• Tear-off. Some insurers require a full new roof, not an overlay, for the credit ^{6 7}.
• Roof size. Measured in roofing squares.
• Paperwork. In Texas, the contractor fills out a form for TWIA credit ⁴.
• Offsets. An insurer credit or a state grant can offset part of the cost over time; ask before you sign.

How to get an impact-rated roof the right way

These are the steps for you as the owner. The roof itself is work for a licensed roofer, not a do-it-yourself job.

1. Call your insurer. Ask if it gives a credit, which classes count, whether it keeps a list of approved products, and what proof it needs ⁶.
2. Pick a product with a current UL 2218 class, or FM 4473 for rigid tiles ³.
3. Get the product name, class and listing number written into the contract.
4. Plan for a full tear-off if your insurer requires a new roof ⁶.
5. Have the roofer install it to the maker's instructions; a bad install can void a listing or warranty.
6. Keep the bundle wrappers or labels, the invoice and any form your insurer or state needs. In Texas, the TWIA form is TDI form PC068 ⁴.
7. Send the proof to your insurer and check that the credit shows on your next bill.

Caring for an impact-resistant roof

• Have a roofer look at the roof after any hail storm, even if you see nothing from the ground.
• Keep your install papers and photos in one place for a claim.
• Keep gutters clear and trim branches that rub the roof.
• Do not walk the roof yourself; let a roofer with fall protection do it.
• Tell your insurer if you replace part of the roof with a different product, since that can change the credit.

Warning signs and problems to watch

• Dark spots where granules were knocked off
• Soft or bruised spots that feel spongy
• Cracks or splits, especially at edges and corners
• Dents in metal vents, gutters and flashing, a sign the roof took hits
• A roofer who says "hail-proof"; no test makes that claim
• A seller who cannot show the UL 2218 class or listing for the product

Standards and rules that apply

The model building code does not require impact-rated shingles in most places. The ratings come from test standards, and the credits from insurers and state programs.

Rules vary by state and change over time. Check your state insurance department and your insurer.

Sources: [1] [3] [4] [5] [8] [2]

Impact ratings vs other roof ratings

IBHS buys shingles from stores and fires lab-made hailstones at them, looking at granule loss, dents and cracks ⁹. That is a different question from UL 2218's pass or fail.

Common misconceptions

Myth Class 4 shingles are hail-proof.

Reality No test says that. UL 2218 uses new material, and weathering lowers most products' hail resistance ¹.

Myth Every insurer gives the same discount.

Reality The Texas Department of Insurance says the amount is set company by company ⁴.

Myth Any new roof with Class 4 shingles earns the credit.

Reality Insurers can add rules, such as no overlays or a certification form ⁶.

Myth UL 2218 and FM 4473 are the same test.

Reality UL 2218 drops steel balls; FM 4473 fires ice balls at rigid roofing ^{3 1}.

Myth The rating covers dents and lost granules.

Reality UL 2218 looks for openings such as cracks and tears, not looks ².

Your state, your insurer and your climate

Credits depend on where you live. In Texas, the department of insurance says each company sets its own amount and Class 4 gets the highest, and TWIA has its own form ⁴.

In Oklahoma, the state runs a grant program ⁸. In Alabama, one insurer's guideline counts Class 3 or 4 non-wood roofs, except synthetic polymer, on new homes or full replacements only ⁷.

We did not load a source for every state, so we do not list other state programs. Your state insurance department's consumer pages are the place to start. Then call your insurer.

Climate matters too. If your area sees hail often, an impact-rated roof is worth pricing. If hail is rare, the credit may be small or not offered, and the choice comes down to other factors.

Should you pay for impact-resistant shingles?

• Price them if you live where hail is common, you are replacing the whole roof anyway, and your insurer offers a credit.
• Ask your insurer for the credit in writing, by product and class, before you sign a contract.
• Choose Class 4 if you want the highest rating and the highest credit under Texas filings ⁴.
• Do not count on the rating to end hail claims; plan for inspections after storms.
• If you have hail damage now, start with our hail claim estimator.

Keep going

• Storm damage and insuranceHow hail claims and deductibles work
• Storm damage repairWhat happens after a hail storm
• Roof inspectionGetting the roof checked after hail
• Roof replacementWhen a new roof is the right call

Related terms

Hail Damage

Roof damage from hailstones: bruised or cracked shingles, dislodged granules, dented metal, broken tile.

Asphalt Shingles

Asphalt shingles are roofing pieces made from a fiberglass mat coated with asphalt and topped with mineral granules, laid in overlapping rows so water runs off the roof.

Architectural Shingles

Architectural shingles are asphalt roof shingles made from two or more layers bonded together, so each shingle is thicker than a flat strip shingle and gives the roof a textured, three-dimensional look.

Metal Roofing

Metal roofing is a roof covering made of metal sheets, panels or shingles, most often steel, aluminum, copper or zinc, fastened to the roof deck to shed water, snow and sun.

Composite Roofing

Composite roofing is a roof covering made of molded tiles or shingles from plastic polymers, rubber, or blends of the two, shaped to look like natural slate or cedar shake.

Hail Damage Insurance Claim

A homeowners claim for hail damage to a roof, often subject to a separate wind/hail deductible.

Insurance Deductible

An insurance deductible is the part of a covered claim that you pay yourself before your homeowners policy pays the rest.

Also referenced from: Asphalt Shingles, Composite Roofing, Solar Shingles, Ridge Cap, Hurricane Roofing