Class 4 shingles: what the impact rating means in Texas.

Class 4 is the top grade on the impact test that shingles take. A Class 4 shingle can lower your insurance premium, it resists more hail than an ordinary shingle, and it is not hail-proof. Two documents decide what it is worth to you: your insurer's rules for the discount, and the shingle's own warranty, which leaves hail damage to your insurance.

This guide explains the test, what it leaves out, how the products differ off the test stand, and what to keep so the discount actually reaches your premium. If hail has already hit your roof, start with what to do after a hail storm instead.

Shingles and metal panels are rated under UL 2218, the Standard for Impact Resistance of Prepared Roof Covering Materials. Steel balls of four sizes are dropped onto the roofing from heights chosen to give each ball the energy of a falling hailstone of the same size. Each spot is struck twice. The lab then turns the sample over: any crack, tear or split on the back counts as a failure. A shingle that comes through the 2-inch ball earns Class 4.

For scale: the National Weather Service counts a storm as severe once its hail reaches an inch, the size of a quarter, flags golf-ball hail as a considerable threat and baseball hail, 2.75 inches, as destructive. Baseball hail is larger than any ball in the test.

UL 2218 looks for one kind of damage: an opening through the shingle. UL Solutions, which tests products to the standard, said so plainly in 2023: the requirements do not account for denting or granule loss. The Insurance Institute for Business and Home Safety (IBHS) spells out the same rule in its own testing notes: crushed or knocked-off granules, dents, and marks that show only on the top of the shingle are not failures.

That matters because the granules are the shingle's sunscreen. A Class 4 shingle can pass the test and still lose granules in a storm, and a shingle that has lost its granules ages faster in the Texas sun. A Class 4 roof still needs a careful look after real hail, slope by slope.

FM Approvals publishes a second standard, FM 4473, that fires balls of frozen water instead of dropping steel. The ice balls come in the same four sizes as the UL test and are launched to match the energy of real hail, and the sample must show no visible cracking or breakage afterward. The standard was written for rigid roofing such as slate, concrete and clay tile, so it is the rating to ask about on a tile roof.

Some shingles carry both. Owens Corning's Duration FLEX and Duration STORM shingles, for example, are classified Class 4 under both UL 2218 and FM 4473. When a quote says "Class 4", ask which test, and on which product.

There are two common ways to make a shingle impact-resistant. Some makers bond a mesh or scrim to the back of the shingle. Others blend polymers into the asphalt itself, which leaves the shingle looking exactly like an ordinary one. In its 2014 study IBHS found that polymer-modified impact-resistant shingles passed about 20 to 50 percent more of the struck spots than traditional impact-resistant shingles, which typically rely on the mesh, with the widest gap at the larger ball sizes.

Makers often name the polymer, SBS, on the product sheet. It is the detail to ask about when two Class 4 quotes name different products. Stone-coated steel panels carry a Class 4 rating too, and our metal roof vs shingles guide compares them with a Class 4 shingle.

A rating is earned on new samples in a lab. IBHS wanted to know how shingles fare after the supply chain, so in 2013 it bought 22 products from five makers at ordinary suppliers and ran them through the same test. The result was sobering: none of the products, basic or impact-rated, passed more than the Class 2 ball without at least one struck spot failing. The impact-rated shingles still did clearly better than the basic ones, but none of them matched its rating in full.

IBHS now rates shingles with its own method, using lab-made hailstones and scoring dents, tears and lost granules as well as cracks. Its November 2025 round covered 24 impact-resistant products, about 95 percent of the impact-resistant shingles sold in a year. Most rated Good, none rated Excellent, and IBHS says it does not recommend a product rated Marginal or Poor anywhere that sees hail. The full list is on its website, and it is worth checking a product there before you buy.

The Texas Department of Insurance explains how impact-resistant roof credits work. Roofing has to pass UL 2218 and be rated Class 1 to 4, and a Class 4 roof earns the largest credit. The amount is set by each insurance company, and each company decides which test results it accepts, how the material must be labeled and what paperwork it wants. For the Texas Windstorm Insurance Association on the coast, the product itself must carry the lab's label, the impact class, the maker's name, the brand and the year it was made, and the installer fills in the department's form PC068.

In September 2026 the department went further. Its bulletin B-0008-26 encourages every property insurer in Texas to build meaningful, actuarially supported discounts for loss mitigation, names impact-resistant roofing as one, and asks companies to tell policyholders what credits they offer. Owens Corning's own literature puts the practical point simply: higher classes often earn bigger discounts, so check with your insurer before you choose. A discount lowers the premium; it does not change the wind and hail deductible you pay on a claim, which our deductible guide explains.

A Class 4 shingle's own warranty does not cover hail. Owens Corning's literature for its Class 4 shingles says hail damage is specifically excluded from the warranty. CertainTeed's 2026 shingle warranty lists damage from a hailstorm among the things it does not cover at all. The rating lowers the odds of damage; it does not move the cost of damage from you to the maker.

So hail on a Class 4 roof is an insurance question, the same as hail on any roof. Our guide to what homeowners insurance covers on a roof explains how that claim works, and what voids a roof warranty walks through the rest of the warranty.

The test grades the shingle, not the roof. A Class 4 shingle with too few nails, no starter strip along the rakes or a hot, unvented attic under it will not give you the roof the label suggests. The building code requires at least four nails per strip shingle; we use six ring-shank nails on every one and size the attic ventilation on every job. Our shingle roofing page sets three-tab, architectural and Class 4 shingles side by side.

IBHS's 2014 numbers show what the rating buys in practice. At the Class 3 ball, 1.75 inches across, the size of golf-ball hail:

• Impact-resistant architectural shingles passed about 60 percent of the struck spots.
• Basic architectural shingles passed about 35 percent.
• At the 2-inch ball, the gap narrowed to about 40 percent against 30.
• Polymer-modified impact-resistant shingles passed about 55 percent at the 2-inch ball, against about 35 percent for the traditional impact-resistant kind.

Read plainly: an impact-resistant shingle fails less often, not never, and the way it is made changes the odds as much as the label does. Over the many hailstorms a Texas roof sees, fewer failed spots should mean fewer repairs.

1. Call your insurance agent first. Ask what discount a Class 4 roof earns on your policy and what proof the company wants.
2. Ask your roofer for the exact product, its UL 2218 class, and its FM 4473 class if it has one.
3. Look the product up in the IBHS ratings, and prefer one rated Good.
4. Ask whether the shingle is polymer-modified or mesh-backed.
5. Keep a photo of the bundle label, the invoice naming the product, and any installation form, and send copies to your agent.
6. Have the roof inspected after a hailstorm anyway; the rating does not cover lost granules.