Impact-resistant shingles: do they actually lower your premium?

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

UL 2218: what the test actually is

Impact resistance for roof coverings in the United States is defined by UL 2218, the standard for impact resistance of prepared roofing materials. The method is deliberately simple: a steel ball is dropped from a fixed height onto a shingle sample mounted on a deck, and the sample is examined afterward for cracking. There are four classes, and they differ only in the diameter of the ball and the height of the drop.

Two details do most of the work. First, the ball is dropped twice on the same spot — the second impact on an already-stressed area is what separates a genuinely tough shingle from one that survives a single hit. Second, the pass criterion is the condition of the back side of the sample: the technician looks for cracking, splitting or rupture of the mat, examined from behind, not for how the face looks. A shingle can be scarred, dented and stripped of granules on the visible surface and still pass, because the test is asking whether the water barrier is still intact.

Class 4 is therefore a precise and limited statement: this product, in the lab, took two 2-inch steel ball impacts at the same point from 20 feet without cracking through. It is not a rating of granule retention, not a rating of appearance, and not a rating of anything to do with wind. Wind resistance is a separate matter tested under ASTM D3161 or ASTM D7158, and the fiberglass shingle product standard is ASTM D3462. Products are commonly rated under several of these at once, and the numbers get run together in marketing.

FM 4473 and the ice ball

FM 4473 is the other impact test you will see referenced. Instead of a dropped steel ball it uses molded ice balls, propelled at the specimen at speeds intended to approximate the terminal velocity of a hailstone of that diameter. It also defines classes by ice ball size, with the top class using a 2-inch ball.

Ice is not steel. It is less dense, it deforms and shatters on impact, and it spreads its load over a growing contact area as it breaks up. That means a steel ball and an ice ball of the same diameter and speed load a shingle very differently, and the two tests are not interchangeable even where the class numbers line up. Neither is a simulation of real hail, which is irregularly shaped, variable in density, arriving at an angle, and hitting a roof that has been baking in the sun for a decade. Both are repeatable, comparable benchmarks — which is exactly what a standard is for and all it can be.

Why a Class 4 rating is not a warranty

The gap between the test and your roof is worth being blunt about.

• The lab sample is new. Testing is done on fresh product. Asphalt stiffens and embrittles with every year of thermal cycling and oxidation, so the tested performance is the performance of a shingle on day one. A Class 4 roof at fifteen years is not the shingle that was tested. This is the same aging curve described in roofing materials and how they handle hail.
• The energy is fixed. There is one drop height and one mass. Real hail arrives across a continuum of sizes, densities and speeds, and wind-driven stones can exceed the test energy comfortably. See what size hail actually damages a roof.
• The pass criterion is a fracture, not the whole loss. Granule loss, scarring and functional damage to vents, flashings and gutters are not covered by the rating at all. A Class 4 roof in a big storm can still generate a legitimate claim.
• Installation still governs. Nailing pattern, sealant activation, deck condition and detailing decide as much as the shingle does.

Two different ways to pass the same test

Two shingles can both carry a Class 4 rating and behave very differently, because manufacturers reach the rating by different routes.

SBS-modified asphalt. Styrene-butadiene-styrene rubber is blended into the asphalt binder, making the shingle elastomeric. It stays flexible at lower temperatures and responds to an impact by deforming and recovering rather than cracking. The toughness is a property of the material itself, distributed through the shingle.

Rigid shingles with a laminated reinforcement. A reinforcing film, scrim or backing is bonded to the underside of an otherwise conventional shingle. The mat may still be stressed by an impact, but the reinforcement holds the assembly together so no crack propagates through to the back face, which is what the test measures.

Both are legitimate engineering. They are not equivalent in the field. The SBS route changes cold-weather behavior and impact recovery across the surface; the reinforcement route is more targeted at the failure mode the standard checks for. When you compare quotes, look at what the product data sheet says about the construction, not just at the class number on the brochure. The impact-resistance comparator lays the classes and constructions out side by side.

The insurance credit and what it applies to

The premium credit is real and it is also routinely misdescribed. Here is the accurate framing.

Many carriers writing homeowners policies in hail-prone states offer a rating credit for a roof covering with a documented UL 2218 Class 4 rating. The size of the credit varies by carrier, by state and by rating plan; some carriers offer nothing at all. Several states have adopted rules that require or encourage insurers to make such mitigation credits available, and the specifics differ by state and change over time — your state department of insurance is the authority on what applies where you live.

Two things narrow the effect more than most homeowners expect:

• It applies to the wind and hail portion of the premium, not the whole bill. Liability, personal property, medical payments and other coverages are unaffected, so a headline percentage off one component is a smaller percentage off what you actually pay.
• It is a rating factor, not a coverage change. The credit does not lower your wind and hail deductible, does not convert an actual cash value roof settlement into replacement cost, and does not remove a cosmetic damage exclusion. If your policy settles the roof on actual cash value rather than replacement cost, that is a much bigger number than the credit and it is worth negotiating first.

How to document it with your carrier

Credits are not applied automatically. You have to prove what is on the roof. Assemble, before the installer leaves:

1. The manufacturer product data sheet or certification document naming the exact product and showing its UL 2218 classification. A generic brochure is not enough; carriers want the specific product line and, often, the specific color line.
2. The installer certificate or final invoice naming the product installed, the address, the square count and the completion date.
3. Photographs of the shingle wrappers on site showing the product name and class markings, plus photographs of the finished roof.
4. Any roof certification form your carrier requires — some have their own form that the contractor must sign.

Send them to your agent and ask, in writing, for the credit to be applied and for confirmation of the effective date. Keep the packet. It is also the fastest way to establish roof age and material if you ever file a claim, which matters throughout the claim process.

What the upgrade costs

Note that the delta is smaller than it looks when you are already replacing the roof, because tear-off, deck repair, underlayment, flashing, vents and labor are the same either way. The incremental decision is only the covering.

Honest payback math

The upgrade pays back through three separate channels, and only one of them is the premium credit.

Short version: in a frequent-hail metro, on a roof you are replacing anyway, on a house you intend to keep, the case is good and it rests mainly on avoided claims rather than on the discount. Everywhere else, price it honestly against a standard architectural roof and be sceptical of anyone who leads with the premium saving.

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 standard for impact resistance of prepared roof covering materials and its Class 1 to Class 4 classification
• Insurance Institute for Business and Home Safety -- research on impact-rated roof coverings and resilient roofing
• National Association of Insurance Commissioners -- state insurance regulation and mitigation credit rules
• Insurance Information Institute -- background on hail losses and mitigation discounts
• NOAA NCEI Severe Weather Data Inventory -- hail frequency data behind the storm history used on this site

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
• Granule loss: the damage you can see from the gutter
• Repair or replace after hail?
• Metal vs asphalt in hail country
• What a roof replacement costs in 2026