Impact-Resistant (Class 4) Shingles: UL 2218, Cost and Insurance Credits

Impact-resistant shingles are roofing products that passed a lab impact test, and the rating you will see most often is UL 2218, Class 1 through Class 4. For Class 4, the top class, a 2-inch steel ball is dropped from 20 feet onto the same spot twice, and the shingle must show no tear, fracture or crack that goes through it (as summarized in IIBEC Interface, May 2020). Two inches is also the hail size at which the NOAA Storm Prediction Center classes a thunderstorm as “significant severe” (see the hail size chart), but a pass is not a promise about real hail: the UL 2218 scope says “there is no currently established direct correlation” between roofing performance under hailstones and under steel balls. This Old House (June 2026) says Class 4 shingles “cost 10%–20% more than standard options.” Premium credits depend on your insurer and state; Texas and Minnesota have written rules.

What the UL 2218 test does

According to IIBEC Interface, the protocol uses “four sizes of steel ball bearings dropped from various heights” to match the energy of similar-sized hailstones. UL Solutions dates the standard to the 1990s; the current edition was last revised May 28, 2024. The Class 4 impact carries almost seven times the energy of Class 1 (our arithmetic).

Class	Steel ball diameter	Drop height	Impact energy
Class 1	1¼ inches	12 feet	3.53 ft·lbf
Class 2	1½ inches	15 feet	7.35 ft·lbf
Class 3	1¾ inches	17 feet	13.56 ft·lbf
Class 4	2 inches	20 feet	23.71 ft·lbf

UL 2218 impact parameters as reproduced in IIBEC Interface, May 2020, Table 1.

The lab aims at weak places, “including corners, edges, unsupported areas,” as well as well-supported parts of the shingle, with two hits within ½ inch of each other. To pass, the product “cannot develop any tears, fractures, or cracks that extend through the product and are visible under 5X magnification.” Crushed granules and dents count as cosmetic and “are permitted.” The standard covers overlapping products on slopes of 2:12 and steeper; low-slope roofs have a separate standard, UL 2218A.

FM 4473: the ice-ball test for tile and slate

Under steel-ball drops, IIBEC Interface notes, rigid products “rarely achieved better than a Class 1 or Class 2 UL-2218 rating.” FM Approvals’ ANSI/FM 4473 (re-affirmed October 10, 2020) is written for “tiles or planks from materials such as slate, concrete or clay.” It fires ice balls of the same four diameters, 1¼ to 2 inches, under the same Class 1–4 labels. FM Approvals writes that an ice ball “simulates the worst case hailstone” because it is generally harder and denser than hail. A passing sample shows “no evidence of visible cracking or breakage” and no other damage such as splits or punctures.

What a Class 4 label does not tell you

How an aging roof will do. UL 2218 “does not evaluate the effect of weathering, temperature, aging or similar effects.”
A guarantee. In a 2014 IBHS paper, the authors write that higher-rated products “should theoretically reduce the severity and frequency of damage,” but the ratings do not promise a storm will leave none.
Dents and granule loss. UL Solutions says the requirements “do not account for denting or granule loss damage that a homeowner or insurance adjuster can observe.” See what hail damage looks like on a roof.
How ice behaves. Engineers from Haag wrote that the steel balls, “much heavier than hail,” strike at lower speeds, so UL 2218 “is considered an indexing test.” In their lab, five heavyweight shingles sold with UL ratings showed “larger and more frequent fractures” under ice balls than under steel balls of the same class.
Which impact-resistant product to pick. When IBHS tested eight impact-resistant shingles on the market in 2018, “product performance ranged from Excellent to Poor.”

IBHS hail ratings and the FORTIFIED hail supplement

The Insurance Institute for Business & Home Safety (IBHS), a nonprofit, buys asphalt shingles from retail stores, hits them with lab-made hailstones and scores dents, tears and granule loss, updating the scorecard every two years. FORTIFIED’s October 2025 advisory says the ratings due November 1, 2025 cover 25 products, about 90% of the impact-resistant shingle market.

For the optional Hail Supplement to FORTIFIED Roof, IBHS’s voluntary construction and re-roofing program, asphalt shingles must be rated “Good or Excellent” on the IBHS ratings current when the roof goes on; metal panels and low-slope systems need UL 2218 Class 4 (as FORTIFIED words it), and tile needs FM 4473 Class 4.

What Class 4 shingles cost

The cost guides we read don’t list an installed price per square foot for Class 4 shingles on its own line. They give the extra over standard shingles:

Source	Date	What it says
This Old House, Oklahoma roof guide	Jun 12, 2026	Class 4 shingles “cost 10%–20% more than standard options”
This Old House, Nebraska roof guide	Jun 17, 2026	impact-resistant shingles “cost 10%–20% more than standard options”
Fixr	Aug 2, 2022	“up to 20 percent more than regular asphalt shingles” in the text, but “Cost 20+ percent more than regular, non-class shingles” in its list of cons
Oklahoma Insurance Department	Oct 2, 2015	“Typically, Class 4 roofing materials for a house cost $1,800 to $2,500 more than lower-rated shingles”

This Old House (April 2026) adds that “the labor shouldn’t end up being any more expensive.” It prices architectural shingles at $2 to $4 per square foot for materials alone and says Class 3 and Class 4 products “typically fall at the higher end.”

For the base, Fixr (January 2026) puts architectural shingles at $4 to $8 per square foot. Tear-off is a separate line: Fixr says removal and disposal add $50 to $150 per square (100 square feet) when billed separately. More on the whole job in hail damage roof replacement.

Insurance premium credits: Texas and Minnesota

Texas. The Texas Department of Insurance (TDI) says impact-tested roofing is classed 1 to 4 and “A Class 4 roof covering would receive the highest premium credit.” Each insurance company sets the amount and decides which tests, product labels and paperwork it accepts. For the Texas Windstorm Insurance Association (TWIA), the product must be rated under UL 2218 and carry the testing lab’s label plus its class, maker, year and brand, and the contractor fills out TDI form PC068. In 1998, Commissioner’s Bulletin B-0030-98 set mandatory credits by class and territory: for Class 4, from 4% to 35% of the basic homeowners premium, with a separate table for dwelling policies (up to 46% of the extended coverage premium), plus an optional endorsement excluding cosmetic hail damage on credited roofs. TDI’s current page instead leaves the amount to each company. In Bulletin B-0008-26 (September 16, 2026), TDI encouraged insurers to build actuarially supported premium savings for mitigation, impact-resistant roofing included.

Minnesota. Minnesota Statutes §65A.298 (2023) requires insurers to give a premium reduction or lower rate to homes designated FORTIFIED with a hail supplement, shown by an IBHS certificate, on policies that include wind coverage. A Class 4 label alone does not qualify. Commerce Bulletin 2026-1 (March 23, 2026) uses 35%, 38% and 40% of the wind/hail premium (Fortified Roof, Silver and Gold, each with hail) as review thresholds; filings below them may be asked for actuarial support. The bulletin covers filings made on or after that date, not earlier approved ones, and the thresholds are benchmarks, not a promised percentage.

Wherever you live, the Oklahoma Insurance Department’s 2015 advice holds: check with your insurer before replacing the roof. Ask which class it accepts, what proof it wants, how the credit shows on your declarations page, and whether a cosmetic damage exclusion comes with it. The policy terms are explained in wind and hail deductibles.

Common questions

Are Class 4 shingles hail-proof?

No. UL says steel-ball results have no established direct correlation with hailstone performance, and dents pass as cosmetic.

Are Class 4 shingles worth it?

It depends on the price gap in the cost table above, your insurer’s credit and how often large hail reaches you. In Texas each insurer sets the credit, so ask for the figure before you sign.

How can I tell if my roof has Class 4 shingles?

Ask the roofer who installed it for the product name and UL 2218 class, or check the invoice and wrapper. Stay on the ground; a licensed roofer can confirm the product up close.

Do impact-resistant shingles lower home insurance?

They can. TDI’s home insurance guide lists an impact-resistant roof among features that may lower a premium, with each company deciding the amount. Minnesota ties its required reduction to a FORTIFIED designation with a hail supplement.

Questions to ask your roofer

Which product are you quoting, and what is its UL 2218 class (or FM 4473 class for tile)?
What is its current IBHS hail rating, if it is an asphalt shingle?
How much more is it than the architectural shingle you would otherwise install?
Does the quote include tearing off and hauling away the old roof?
Will you fill out the paperwork my insurer asks for, such as TDI form PC068 in Texas?
Are you listed in the FORTIFIED directory?

For vetting a contractor, see how to choose a roofer after hail. To price a full replacement source by source, use the roof and siding cost calculator.