Class 3 and Class 4 Roof Ratings: What They Mean for Your Home

The article explains what Class 3 and Class 4 roof impact ratings are, how they are tested, which materials meet those standards, and why they matter for homeowners, insurers, and building officials. Understanding the difference between Class 3 and Class 4 helps homeowners make informed choices about durability, insurance discounts, and storm readiness.

Rating	Impact Resistance	Common Materials	Typical Benefit
Class 3	Resists moderate impact	Some asphalt shingles, metal with backing	Better protection, possible insurance savings
Class 4	Highest certified impact resistance	Specialized asphalt, stone-coated metal, rubber	Best storm protection, higher discounts

What The Term “Class 3” And “Class 4” Mean

Class 3 and Class 4 are impact resistance ratings assigned to roofing materials after standardized testing. These ratings indicate how well a roofing product resists damage from flying debris such as hail. Class numbers range from 1 to 4, with Class 4 representing the highest performance level under the test protocols commonly accepted in the U.S.

How Impact Ratings Are Tested

Testing for impact resistance follows standardized laboratory protocols to reproduce the effect of hailstones hitting roofing products. Two widely recognized standards are UL 2218 and FM 4473, which use steel ball projectiles at defined sizes and velocities to simulate hail impacts.

UL 2218 Test Procedure

The UL 2218 method fires steel balls of varying diameters at roofing samples mounted on a deck. The test examines for tearing, cracking, or penetration. Class 3 requires passing intermediate sized impacts while Class 4 requires surviving the largest ball impacts without significant damage.

FM 4473 Test Procedure

FM Global’s FM 4473 is another industry standard with similar ballistic impact simulation and documentation criteria for approval. Products certified under FM 4473 have demonstrated durability to insurers and building professionals.

Difference Between Class 3 And Class 4

While both classes indicate impact resistance, the difference is in the scale of simulated hail the product can withstand. Class 3 materials withstand smaller to medium-sized simulated hail, while Class 4 materials survive the largest specified impacts without severe damage.

Class 4-rated roofing typically shows no cracks, tears, or loss of granular surface that would lead to leaks. Class 3 may show minor surface effects but still maintain integrity against most real-world hail events that cause cosmetic damage rather than structural failure.

Common Roofing Materials And Which Class They Reach

Different materials achieve impact ratings based on composition, layering, and reinforcement. Not all products within a material category meet Class 3 or 4 — the specific product certification matters most.

• Asphalt/Shingle Roofing: Designer laminated shingles and some impact-modified asphalt shingles can reach Class 3 or Class 4 when manufactured with reinforced mat and polymer modifiers.
• Metal Roofing: Stone-coated metal and heavy-gauge metal with backer layers often achieve Class 4; thin panels without backing may not.
• Rubber/Polymer Roofing: Synthetic slate, rubber membranes, and certain polymer-based shingles can achieve Class 3 or 4 due to their flexibility and impact absorption.
• Concrete/Clay Tile: Tile can be brittle; some engineered concrete or stone-coated products may reach higher classes, but many tiles fail brittle-impact tests.

Why These Ratings Matter To Homeowners

Impact ratings matter for three practical reasons: protection, finances, and compliance. High impact ratings reduce the probability of roof replacement after hail events and often lower insurance premiums.

Insurers use Class 3 and Class 4 certifications when underwriting and pricing policies. Many insurance carriers offer premium discounts for Class 4 roofs because they lower claim frequency and severity for hail damage.

Insurance, Rebates, And Building Codes

Local building codes and incentive programs may reference impact ratings. Insurance carriers commonly provide credits for Class 3 or higher, with larger discounts typically tied to Class 4 certifications.

Municipalities in high-hail regions sometimes require or strongly recommend higher-impact roofing for new construction or re-roofing. Homeowners in such zones should confirm code requirements and potential rebate programs before selecting materials.

How To Verify A Product’s Rating

Homeowners should ask for product certification documents from manufacturers or contractors. Look for UL 2218 or FM 4473 test reports and the product’s specific Class designation.

Certified products carry labels or documentation describing the test lab, test standard, and date. Independent verification can be obtained through manufacturer websites or third-party testing laboratories.

Selecting The Right Roof For Location And Risk

Choosing between Class 3 and Class 4 depends on local hail frequency, home insurance factors, and budget. In areas with frequent severe hail, Class 4 is usually the better long-term investment.

Homeowners should weigh upfront costs versus potential savings from avoided roof replacements and insurance discounts. A local roofing contractor or inspector familiar with regional weather patterns can advise on optimal choices.

Cost Considerations And Longevity

Class 4-rated products can cost more upfront due to enhanced materials and manufacturing processes. However, the extended service life and reduced likelihood of catastrophic hail damage often offset the initial premium over time.

Consider total cost of ownership including expected maintenance, warranty terms, and potential storm-related repairs when comparing products.

Installation And Warranty Implications

Proper installation affects performance; even a Class 4 material can fail if installed incorrectly. Manufacturers usually require certified installers to maintain warranty validity and to ensure rated performance.

Warranties for impact-rated roofs may include specific terms about hail and wind; consumers should review warranty language carefully, including coverage limits and required inspections.

Maintenance, Inspection And Post-Storm Steps

Routine maintenance prolongs impact performance. After severe weather, homeowners should document any visible damage, file claims promptly, and request inspections from qualified roofers.

Replacing only damaged sections can be complicated if matching certified material is no longer available; owners may prefer whole-roof upgrades to maintain consistent impact protection.

Common Misconceptions

One misconception is that Class 4 roofs are indestructible. Class 4 indicates superior resistance but not absolute immunity to extremely large hail or falling trees.

Another misconception is that all metal roofs are Class 4. Metal roofs vary widely; performance depends on gauge, coating, and backing materials, not merely the material category.

Questions To Ask A Contractor Or Manufacturer

• Can You Provide The UL 2218 Or FM 4473 Test Report For This Product?
• Is The Installer Certified By The Manufacturer To Maintain The Warranty?
• What Insurance Discounts Have Other Customers Received For This Product?
• How Does This Product Perform In Wind And UV Tests In Addition To Impact Tests?

Practical Examples And Use Cases

In high-hail regions such as parts of the Midwest and Rocky Mountain states, many homeowners upgrade to Class 4 shingles or stone-coated metal during roof replacement cycles. These upgrades reduce claim frequency and stabilize long-term roofing costs for the property.

Urban and suburban homeowners who keep properties for decades often select Class 4 materials to minimize both repair disruption and resale risks tied to hail damage history.

Where To Find More Information

Authoritative resources include UL’s official publications, FM Global approvals, manufacturer technical data sheets, and local building code offices. Consumer-focused resources such as state insurance departments and university extension services provide regional guidance on hail risk and insurance credits.

Homeowners should consult these sources and obtain written certifications before committing to a specific roofing product.

Final Practical Tips For Homeowners

Record the product certification and store warranty documents securely. When planning a re-roof, obtain multiple bids that reference certified Class ratings and follow up with insurers about potential premium savings.

Prioritize installer credentials and documented test reports over marketing claims. Choosing certified Class 3 or Class 4 roofing materials is a decision that balances upfront cost, local risk, and long-term protection.