Class 4 Impact Shingles in Colorado: A Deep Dive

What UL 2218 actually measures

UL 2218 is a steel ball drop test. A 2-inch steel ball is dropped from a fixed height onto the shingle in a controlled lab setting. The shingle must show no rupture, fracture, or crack on the back surface for the rated class. UL 2218 has four classes, with Class 4 the highest. Class 4 corresponds to the 2-inch steel ball dropped from 20 feet.

The test measures impact resistance to a single sharp impact at one point on a new shingle. It does not measure repeated impact, aged shingle performance, hail of irregular shape, or the cosmetic granule displacement that drives most insurance claims. Granule loss is excluded from impact failure under the test.

What the IBHS test adds

The Insurance Institute for Business and Home Safety launched its hail rating system in 2019 to address the limitations of UL 2218. The IBHS test fires actual ice balls of varying sizes at shingles using compressed air, and grades the shingle on a scale from one to five. The test is conducted on shingles aged in a UV chamber to approximate field-aged condition rather than only on new product.

An IBHS rating of 4 or 5 indicates strong real-world hail performance on aged product. The IBHS rating is published per shingle product on the IBHS website and does not perfectly correlate with UL 2218 Class 4 status. Several Class 4 shingles carry IBHS ratings of 2 or 3 because aged film performance does not match new film performance.

SBS-modified versus scrim-reinforced construction

Class 4 status can be achieved through two different construction approaches, and they perform differently in the field.

• SBS-modified bitumen shingles use styrene-butadiene-styrene polymer in the asphalt to produce a flexible, rubber-like material that absorbs impact energy by deforming. Malarkey Vista AR, Highlander NEX AR, and Legacy AR are the most commonly installed SBS-modified products on the Front Range.
• Scrim-reinforced shingles use a polymer mesh or fiberglass scrim laminated to the back of a standard asphalt shingle. The scrim resists the steel ball penetration required by UL 2218 but does not change the asphalt's behavior under impact. GAF Armor Shield and Owens Corning Duration Storm use this approach.
• Field experience and the IBHS aged-shingle test data both indicate that SBS-modified shingles maintain impact performance better as they age. Scrim-reinforced shingles can pass UL 2218 when new but show more granule loss and surface damage from aged-product hail strikes.

Brand and product comparison

The Class 4 market on the Front Range is dominated by four manufacturers. Each has multiple product lines at different price points.

• Malarkey: Vista AR and Highlander NEX AR are SBS-modified, IBHS rated, and carry algae resistance. Malarkey is widely regarded by Front Range roofing crews as the strongest aged-shingle hail performer.
• Owens Corning: Duration Storm uses a polymer scrim on the back of the standard Duration shingle. The TruDefinition Duration FLEX is the SBS-modified upgrade. The Storm product is more common, the FLEX product is less common but performs better in IBHS testing.
• GAF: Timberline Armor Shield II is the scrim-reinforced Class 4 product. The newer Timberline UHDZ uses an enhanced shingle with improved performance, though the impact-rated configuration is specific.
• CertainTeed: NorthGate ClimateFlex uses an SBS-modified construction and is the Class 4 product in the Landmark family. ClimateFlex carries IBHS ratings comparable to Malarkey.

Insurance discount eligibility and amounts

Carriers apply the Class 4 discount differently. The 2018 Mile High Roofing Cooperative survey and subsequent annual updates show a wide range across carriers.

• Typical Class 4 discount range across major carriers: 10 to 35 percent on the wind and hail portion of the homeowner premium.
• Typical Front Range outcome: 25 to 28 percent reduction on the wind and hail premium, which translates to roughly 8 to 12 percent of the total homeowner premium.
• USAA and Allstate apply discounts on the higher end of that range. State Farm and Farmers commonly apply discounts in the middle of the range. American Family discounts vary by underwriting unit.
• Most carriers require a Class 4 certificate from the contractor, the manufacturer product brochure, and either an installation invoice or a roof inspection report to apply the discount. Some carriers also require IBHS rating documentation.
• The discount typically applies for the life of the roof or for a defined period such as ten years, after which the carrier may require recertification.

Cost premium and breakeven analysis

The Class 4 upgrade premium varies by brand and tier. The breakeven calculation depends on the discount applied and the homeowner's premium.

• Typical Class 4 upgrade premium over equivalent standard architectural shingle on a 30-square Front Range job: 800 to 2,200 dollars.
• Typical annual premium savings from the Class 4 discount on a Front Range homeowner policy: 200 to 700 dollars depending on policy size and carrier.
• Typical breakeven period for the upgrade premium based on insurance savings alone: 2 to 8 years.
• Additional value from reduced claim frequency, reduced deductible exposure, and improved aged shingle performance is real but harder to quantify. Front Range insurance carriers track Class 4 roofs as a separate cohort and report meaningfully lower claim frequency on equivalent storms.

What Class 4 does not do

Class 4 is not hail proof. It is hail resistant. The marketing in this category sometimes overstates the protection and creates false expectations.

• Class 4 shingles can still suffer cosmetic granule displacement from hail, and most carriers exclude cosmetic damage from coverage on Class 4 product.
• Class 4 shingles can still be damaged by hail above 2.5 inches in diameter. Hail of that size is documented several times per year on the Front Range.
• Class 4 status does not change the manufacturer's wind rating, ventilation requirements, or installation specifications. The same accessory components and ventilation are required.
• Class 4 status does not extend the manufacturer warranty in most cases. The base warranty applies. Some manufacturers offer enhanced wind coverage when accessory components are installed.

Recommendation framework for Front Range homeowners

The decision framework for Class 4 in 2026 is relatively settled.

• On any Front Range home, the breakeven on Class 4 typically arrives within two to eight years of installation. The upgrade is economically rational on most jobs.
• Among Class 4 options, SBS-modified products from Malarkey and CertainTeed ClimateFlex carry better aged-shingle performance based on IBHS testing.
• Scrim-reinforced products from GAF and Owens Corning meet the discount requirement and cost less, with somewhat lower aged-shingle performance.
• Confirm with the homeowner's specific carrier that the chosen product qualifies for the discount before signing. A small number of underwriting units restrict the discount to specific brand-and-product combinations.