By The Roofing Brief Team. Last reviewed: October 2026.
Impact-resistant (Class 4) shingles are asphalt shingles, usually made with SBS polymer-modified asphalt, that pass the UL 2218 test at its top level: a 2 inch steel ball dropped twice from 20 feet onto the same spot without a crack or rupture. Standard architectural shingles are conventional laminated asphalt shingles, and the flagship lines often stop one class lower: on the State Farm Roofing Premium Credits Product Listing (revised October 1, 2026), GAF Timberline HDZ, Owens Corning TruDefinition Duration and CertainTeed Landmark are UL 2218 Class 3, while GAF Timberline AS II, Owens Corning TruDefinition Duration Storm and CertainTeed Landmark ClimateFlex are Class 4. In the impact resistant vs standard shingles decision, the Class 4 line buys better hail resistance and, with some carriers, a premium credit; it costs about $8 to $13 per sq ft installed against $5 to $8 for standard architectural, per our 2026 Roofing Cost Report.
What are impact-resistant (Class 4) shingles?
Impact-resistant shingles are asphalt shingles engineered to withstand hail and flying debris without cracking, and Class 4 is the top rating under the UL 2218 test. In that test, a steel ball 2 inches in diameter is dropped from 20 feet onto the shingle, and a Class 4 sample must not crack or split when struck twice in the same spot, per Owens Corning’s Class 4 explainer and GAF’s Timberline AS II product page. Most impact-rated shingles reach this grade by using SBS (styrene-butadiene-styrene) polymer-modified asphalt, a rubberized binder that flexes on impact and returns toward its original shape instead of shattering; GAF says its SBS formula also lets AS II lay flatter at 40°F or higher than its standard shingle.
| UL 2218 class | Steel ball diameter | Drop height | Source |
|---|---|---|---|
| Class 1 | 1 1/4 in | 12 ft | Owens Corning UL 2218 class table |
| Class 2 | 1 1/2 in | 15 ft | Owens Corning UL 2218 class table |
| Class 3 | 1 3/4 in | 17 ft | Owens Corning UL 2218 class table |
| Class 4 | 2 in | 20 ft | Owens Corning; GAF Timberline AS II page |
Class 4 is the highest of four UL 2218 grades (Class 1 through Class 4), and it is the level most insurers reference for hail discounts. A separate test, FM 4473, uses molded ice balls fired at the shingle; Owens Corning lists Duration Storm and Duration FLEX under both UL 2218 and FM 4473 Class 4, and State Farm’s listing accepts either standard by product name. Since 2019 the Insurance Institute for Business and Home Safety has also rated impact-resistant shingles with lab-made hailstones; its fourth edition (November 2025) covered 24 products, about 95% of impact-resistant shingles sold annually, and none earned its top Excellent rating, while most earned Good. IBHS says it does not recommend products rated Marginal or Poor in hail areas. Common Class 4 lines include GAF Timberline AS II, CertainTeed NorthGate ClimateFlex, Owens Corning TruDefinition Duration Storm, and Malarkey Legacy.
What are standard architectural shingles?
Standard architectural shingles, also called laminated or dimensional shingles, are the most common residential roofing product in the United States. They are built from two or more layers of asphalt-coated fiberglass mat bonded together for a thicker, layered look. Their impact rating varies by line: GAF Timberline HDZ, Owens Corning TruDefinition Duration and CertainTeed Landmark are UL 2218 Class 3 on State Farm’s October 2026 listing, and lines not on that listing may carry no impact class at all.
Standard architectural shingles are not fragile, and on the big brands their warranty and wind terms match the Class 4 line. GAF Timberline HDZ carries the same Lifetime Limited warranty, ASTM D3161 Class F and ASTM D7158 Class H wind ratings, and WindProven limited wind warranty with no maximum wind speed (when installed with four qualifying GAF accessories) as Timberline AS II, per GAF’s product pages. The gap versus Class 4 is specifically hail and impact performance: a Class 3 shingle is tested with a 1 3/4 inch ball from 17 feet rather than a 2 inch ball from 20 feet.
Impact resistant vs standard shingles: side-by-side comparison
The table below compares Class 4 impact-resistant shingles against standard architectural shingles on the points that decide most quotes, using the GAF and Owens Corning flagship pairs as the example where a maker publishes the figure. Cost rows come from our 2026 Roofing Cost Report and move with region, pitch and tear-off.
| Factor | Impact-resistant (Class 4) | Standard architectural | Source |
|---|---|---|---|
| Impact rating (UL 2218) | Class 4 (2 in ball, 20 ft) | Class 3 on GAF HDZ, OC Duration, CertainTeed Landmark; none on some lines | State Farm listing, Oct 1, 2026 |
| Core material | SBS polymer-modified asphalt (GAF AS II, OC Duration FLEX) or a polymer backing (OC Duration Storm WeatherGuard) | Conventional asphalt, fiberglass mat | GAF and Owens Corning product pages |
| Manufacturer warranty | Lifetime Limited (GAF AS II; OC Duration Storm) | Lifetime Limited (GAF HDZ; OC Duration) | GAF and Owens Corning product pages |
| Hail coverage in that warranty | None: GAF says AS II is not warranted against hail damage | None | GAF Timberline AS II page |
| Installed cost | Roughly $8 to $13 per sq ft | Roughly $5 to $8 per sq ft | 2026 Roofing Cost Report |
| GAF’s own price tier | $$$$ (Timberline AS II) | $$ (Timberline HDZ) | GAF product comparison widget |
| Wind rating | ASTM D3161 Class F; OC Duration Storm up to 160 mph with qualifying install | ASTM D3161 Class F and D7158 Class H (GAF HDZ) | GAF and Owens Corning product pages |
| Pieces, bundles and nails per square | 64 pieces, 3 bundles, 256 nails (GAF AS II) | 64 pieces, 3 bundles, 256 nails (GAF HDZ) | GAF spec tables |
| Insurance credit | Set by each insurer; Texas’s 1998 mandatory schedule ran 4% to 35% | Class 3 credit on some carrier listings; often none | TDI Bulletin B-0024-98; State Farm listing |
| Best for | Hail-prone regions, long-hold owners, insurer-required upgrades | Low-hail regions, tighter budgets, shorter hold periods | Decision table below |
How much more do impact-resistant shingles cost?
Our 2026 Roofing Cost Report puts Class 4 impact shingles at roughly $8 to $13 per square foot installed, against $5 to $8 for standard architectural asphalt. On a 2,000 square foot roof, that is about $16,000 to $26,000 for Class 4 versus $10,000 to $16,000 for architectural, before regional, pitch and tear-off adjustments. The two ranges are national planning figures, so the real gap on your house depends on the specific product lines quoted; GAF’s own comparison tool rates AS II at $$$$ and Timberline HDZ at $$, and its Class 4 Timberline UHDZ at $$$, so some Class 4 lines price closer to standard shingles than others.
Labor is close to identical because the GAF pair installs the same way: 64 pieces, 3 bundles and 256 nails per square for both Timberline AS II and Timberline HDZ, per GAF’s spec tables. Most of the difference therefore sits in the material, so ask for the Class 4 line as a separate line item, including the matching Class 4 hip and ridge cap, which Owens Corning requires for its UL 2218 Class 4 roof system warranty coverage.
| Worked payback example (inputs shown) | Value | How it is calculated |
|---|---|---|
| Roof area | 2,000 sq ft (20 squares) | Input |
| Upgrade cost at range midpoints | $8,000 | ($10.50 minus $6.50) x 2,000 sq ft, 2026 Roofing Cost Report midpoints |
| Example annual premium | $3,000 | Input: use your declarations page |
| Example Class 4 credit | 20% of premium, $600 a year | Input: inside Texas’s historic 4% to 35% band; ask your carrier |
| Simple payback | 13.3 years | $8,000 / $600 |
| Same roof with a 10% credit | 26.7 years | $8,000 / $300 |
Do impact-resistant shingles lower insurance premiums?
In many hail-prone states, Class 4 shingles can earn a homeowners insurance credit, but each insurer sets the size. The best-documented schedule is Texas’s: the Texas Department of Insurance made a roof-covering credit for UL 2218 impact-rated roofs mandatory in 1998 (Commissioner’s Bulletin B-0024-98), at 4% to 35% for Class 4 depending on rating territory, and TDI’s current guidance says each company now sets its own amount. For FORTIFIED roofs in Louisiana, approved filings as of July 1, 2026 run from 1% to 45.62%, per the Louisiana Department of Insurance Act 533 report. State Farm names qualifying lines in its product listing and lists the roofing discount in 26 states, but publishes no percentage.
Whether the upgrade pays back depends on that credit and your hail exposure. At a $600 annual saving, an $8,000 upgrade pays back in about 13 years; at $300, about 27 years. For a state-level breakdown of what carriers and regulators publish, see our guide to impact-resistant shingle insurance discounts by state. Many policies also exclude cosmetic hail damage, and GAF states that Timberline AS II is not warranted to withstand hail damage, so an impact rating protects roof function more reliably than it protects appearance.
Pros and cons of each shingle
Neither shingle wins every situation. The deciding inputs are your area’s hail claim history (Texas logged 811,381 hail loss claims from 2016 to 2018, per the National Insurance Crime Bureau), how many years you will own the home, and the credit your insurer confirms in writing.
Impact-resistant (Class 4) pros:
- Best available UL 2218 impact grade; resists cracking from hail and debris
- Often also FM 4473 Class 4 (Owens Corning Duration Storm and FLEX)
- Can qualify for an insurance credit; Texas’s 1998 schedule ran 4% to 35% for Class 4
- Same 64 pieces and 256 nails per square as the GAF standard line, so labor changes little
Impact-resistant cons:
- Costs more upfront ($8 to $13 vs $5 to $8 per sq ft installed, per the 2026 Roofing Cost Report)
- Credit is set by each insurer and may be small or unavailable in low-hail areas
- Impact rating covers function, not always cosmetic hail marks your policy may exclude
- Not every Class 4 product performs alike: IBHS’s 2025 ratings gave no product its top Excellent rating
Standard architectural pros:
- Lower upfront cost and wide brand and color availability
- Same Lifetime Limited warranty tier and Class F wind rating on GAF Timberline HDZ
- Class 3 on several flagship lines, which some carrier listings still credit
Standard architectural cons:
- Tested only to the 1 3/4 inch, 17 ft Class 3 drop, or not rated at all
- More prone to hail bruising, cracking, and granule loss
- No Class 4 insurance credit
Which should you choose? A decision framework
Choose based on hail exposure, ownership horizon, and insurer behavior rather than the impact rating alone. The table sets the thresholds; the steps below put them in order.
| If your situation is | Choose | Threshold or reason |
|---|---|---|
| Texas, Colorado, Nebraska, Missouri or Kansas (top 5 for hail claims, NICB 2016 to 2018) | Class 4 | Highest hail claim counts; all five are on State Farm’s discount list |
| Payback (upgrade cost / annual credit) shorter than your planned ownership | Class 4 | Example: $8,000 / $600 = 13.3 years |
| Payback longer than your planned ownership and low hail risk | Standard architectural | Insurance math alone will not repay the upgrade |
| Carrier credits only named products | A line on that carrier’s list (State Farm: listing dated Oct 1, 2026) | State Farm: roofing overlaid onto an existing roof does not qualify, except metal roofing |
| Comparing two Class 4 lines | The one with the better IBHS rating | IBHS does not recommend Marginal or Poor products in hail areas |
| Carrier requires a Class 4 system | Class 4 field shingles plus Class 4 hip and ridge | Owens Corning requires matching hip and ridge for its Class 4 system coverage |
- Check your hail risk. If you live in the central hail belt, where the NICB’s 2016 to 2018 counts put Texas (811,381 claims), Colorado (395,025), Nebraska (163,336), Missouri (153,403) and Kansas (146,206) at the top, Class 4 usually earns its premium. In low-hail coastal or northern regions, standard architectural often makes more sense.
- Confirm the insurance credit in writing. Call your carrier before you buy. Ask the exact discount percentage, whether it applies to the full premium or only the wind/hail portion, and which rating (UL 2218 Class 4 or FM 4473) they accept. A confirmed credit can shift the math decisively toward Class 4.
- Match the roof to how long you will stay. If you plan to hold the home 15 years or more, a Class 4 roof has more years to repay the upgrade through credits and avoided hail claims. For a short hold or a home you may sell soon, standard shingles limit upfront cost.
- Run the simple payback. Divide the upgrade cost (the line-item difference between your Class 4 and standard quotes) by your annual insurance saving. If payback lands inside your expected ownership period, Class 4 is the stronger financial choice; if it stretches well beyond it, standard shingles may be the better value.
- Weigh non-insurance benefits. Even without a credit, Class 4 can be worth it in a hail zone because each avoided claim also avoids a percentage wind/hail deductible: on a $400,000 dwelling, a 2% deductible is $8,000 per claim.
For how roof age and material feed into claim costs and premiums, see our research on roof age and hail claim severity and our overview of roofing material types. If you are comparing shingle construction more broadly, our breakdown of asphalt vs fiberglass shingles and what a 50-year shingle rating really means are useful next reads.
Frequently asked questions
Are Class 4 impact-resistant shingles worth it?
Class 4 shingles are usually worth it in hail-prone regions and for owners who plan to stay in a home for many years. The upgrade (about $8,000 on a 2,000 sq ft roof at 2026 Roofing Cost Report midpoints) can be repaid by an insurance credit, which Texas’s 1998 schedule set at 4% to 35%, plus fewer hail claims. In low-hail areas with no credit, standard architectural shingles are often the better value.
What is the difference between Class 4 and standard shingles?
Class 4 shingles pass the UL 2218 impact test with a 2 inch steel ball dropped twice from 20 feet, while flagship standard lines such as GAF Timberline HDZ and Owens Corning TruDefinition Duration are Class 3, tested with a 1 3/4 inch ball from 17 feet. Class 4 products usually use SBS polymer-modified asphalt and can qualify for insurance credits that standard shingles do not.
How much more do impact-resistant shingles cost?
The 2026 Roofing Cost Report puts Class 4 impact shingles at roughly $8 to $13 per square foot installed, against $5 to $8 for standard architectural asphalt. On a 2,000 square foot roof, that is about $16,000 to $26,000 versus $10,000 to $16,000. The actual gap depends on the product lines quoted, so ask for the Class 4 upgrade as a separate line item.
How long do Class 4 shingles last compared to standard?
The major makers do not publish a different service life for their Class 4 and standard lines: GAF Timberline AS II and Timberline HDZ both carry a Lifetime Limited warranty, as do Owens Corning Duration Storm and Duration. The practical difference is hail damage, which can force early replacement of a standard roof in a hail zone, and neither warranty covers hail. Real-world life still depends on climate, ventilation, and installation quality.
Can Class 4 shingles still be damaged by hail?
Yes. Class 4 shingles resist cracking and splitting far better than standard shingles, but very large hail can still bruise or mark them, and IBHS’s 2025 hail ratings gave none of 24 tested products its top Excellent rating. GAF states that Timberline AS II is not warranted to withstand hail damage, and many insurance policies exclude cosmetic hail damage, so impact resistance reduces claims but does not make a roof hail-proof.
Do all insurance companies offer a Class 4 discount?
No. Each insurer sets its own credit, and some offer none. Texas made a credit for UL 2218 impact-rated roofs mandatory in 1998 at 4% to 35% for Class 4, and Louisiana’s approved FORTIFIED filings run from 1% to 45.62% (July 2026). Confirm the amount, the accepted rating (UL 2218 or FM 4473), and the required paperwork with your insurer before choosing Class 4 for the savings alone.