What is an Impact Resistant Shingle?

Better Protection for your Roof

Colorado’s annual hailstorms can cause tremendous damage to vehicles, homes, and businesses. A hailstorm may cause damage to your siding, paint, deck, (signage if a commercial property), shrubs, skylights, flashings, gutters and downspouts, and roof.

As a top roofing company in Denver, Fort Collins, Colorado Springs, and across the Front Range, we are proud to help customers when most they need us the most. Replacing your roof is not something most owners do regularly, and we are experts in the roof replacement and insurance claims process.

When you do next need a roof replacement, some products offer better protection – and that’s a Class 4 Impact Resistant shingle.


What is a Class 4 Shingle?

Impact resistant shingles (also referred to as Class 4 Impact Resistant shingles) are roofing products specially designed to withstand extreme winds, snow, and hail damage. Class 4 shingles are manufactured with an SBS (styrene-butadiene-styrene)-modified asphalt formula, which is also called rubberized asphalt.

These impact resistant shingles earn an impact resistance rating by Underwriter Laboratories (UL), specifically the UL 2218 classification, which is the highest impact resistance rating. UL performed testing that involved dropping a two-inch steel ball into a shingle from a 20-foot height to simulate the impact of hail falling at high speeds and checking whether the product cracks.

The result is that homeowner roofs are nearly impervious to most wind and hail-related damage.

No shingle or roofing material is hail-proof, but a Class 4 Impact Resistant shingle is the most advanced asphalt shingle available.


“I love my new roof. It looks great. Two of my neighbors also had their roofs done with this company and they were pleased as well. It is a big decision to know who to trust when making a big purchase like a roof but Jonathan is honest and reliable and there are no surprises. I highly recommend Metro City Roofing.”

– Bonnie Colby

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A Brief History of the Class 4 Shingle

Until 1996, it was common knowledge that certain roofing materials offered better wind and hail protection than did others, but there was no defining standard. In 1996, several property insurance experts partnered with the Institute of Business and Home Safety (IBHS) and the Underwriter’s Laboratory (UL) to develop the UL 2218 classification – the Standard for Impact Resistance of Prepared Roof Covering Materials. UL 2218 became the national standard for roof impact resistance with a material rating from Class 1 through 4, with a Class 4 rating as the toughest. The result is based on a shingle’s resistance to impact testing with steel balls simulating 90-mph hailstones of varying sizes.

Roofing manufacturers began producing affordable Class 4 residential roofing materials previously unavailable before 1997. Insurance companies within established hailstorm locations started an information campaign informing policyholders, agents, roofers, and state insurance departments about the advantages and impact of this new hail impact resistant shingles, which offered reduced roof maintenance and replacement costs.

With an impact resistant asphalt shingle (also called a modified asphalt shingle), the rubber-like quality prevents hail from fracturing the fiberglass mat and eliminates early deterioration. Further, the flexibility increases wind resistance, making it harder for high winds to blow these shingles off a roof when properly installed.

Class 4 roofing shingles have been manufactured from aluminum, copper, plastic, and resin for years. The higher price has been the primary disadvantage for many homeowners and commercial property owners. With the modified asphalt shingle, many homeowners became able to better protect their roof and home against wind and hail.


Steel ball simulation test

Underwriter Laboratories’ steel ball test simulates the impact of a hailstone using a steel ball on a shingle, focusing on the shingle’s most vulnerable areas, including the edges, corners, unsupported sections, and joints.

The simulation includes the following:

  • Steel balls are dropped – from 12 feet for a 1.25-inch ball and from 20 feet for a 2-inch ball
  • Impact resistant shingles remained intact, even with the 2-inch steel ball
  • To successfully pass the UL 2218 standard, the roof covering, the exposed surface, the back surface, and underneath layers all must show no evidence of tearing, fracturing, cracking, splitting, or rupturing.

description of Class 4 Underwriter Laboratories 2218 Impact Resistance test with a steel ball

Non-impact resistant shingles will endure cracks and ruptures from the same steel ball test. The shingles granules will be knocked off, leaving it exposed to harmful UV damage. Over time, UV rays will degrade a roof and make it vulnerable to leaks.

This hail simulation test is performed on new shingles – not aged shingles that may already be brittle with age or more susceptible to hail damage. Another factor to consider for your home is your roof’s pitch. Steeper pitched roofs are less vulnerable to most hailstorms than lower pitched roofs. Additional considerations include the type of underlayment used, the existing condition of the roof decking, tree coverage, and more.


Four different shingle ratings

The following lists the four impact ratings and the description of the sample’s impact.


4 different ratings and description from Underwriter Laboratories 2218 steel ball test, with a 4 rating being the more durable sample


Today’s Class 4 Impact Resistant Shingles

Asphalt shingle manufacturers like Owens Corning, Certainteed, and GAF offer Class 4 Impact Resistant shingles and complete roof systems with beautiful style and quality, in various shingle designs. Many of these products have a 50-year rating compared to 30-years on a lesser shingle.

For homeowners and building owners with a flat roof, the International Building Code (IBC) requires that flat roofs must be impact resistant, according to section 1504.7, roof coverings installed on low-slope roofs (roof slope < 2:12) shall resist impact damage.

Which Companies Make Class 4 Shingles?

Most asphalt shingle manufacturers make impact resistant shingles that meet the Class 4 rating. We’ll name a few here.


Owens Corning

Owens Corning is a leading asphalt shingle manufacturer in the United States, with corporate headquarters in Toledo, Ohio – and manufacturing right here in Henderson, Colorado.

Owens corning offers a Class 4 IR shingle called Duration Storm and recently added a Duration FLEX.



Certainteed offers a variety of IR asphalt shingles and beyond, such as slate or metal roofing tiles and shake. Asphalt shingles include Northgate IR, Landmark IR, Belmont IR, and Presidential Shake IR.



GAF has two impact resistant shingle options – Timberline Armorshield II and the Grand Sequoia. The Armorshield looks like a traditional dimensional shingle but with Class 4 impact resistance. The Grand Sequoia is a more premium wood-shake look with Class 4 impact resistance.



Tamko offers a Heritage IR shingle. Heritage IR is a laminated, fiberglass asphalt shingle featuring an additional polyester mat, which reinforces the entire shingle.

Homeowner Benefits and Insurance Claims

Impact resistant shingles may cost more, but they deliver a strong return on investment, providing increased damage resistance and reduced maintenance costs. Homeowners may eliminate a costly roof replacement with a future hailstorm too. And, promoting your home has a Class 4 Impact Resistant roof is a selling point when selling a home.

Further offsetting the expense of a roof replacement with a premium Class 4 shingle, many insurance companies offer insurance premium discounts to justify this added expense of a Class 4 new roof. Loss mitigation becomes a homeowner-insurer partnership, where both parties share in the responsibility and associated real savings.

Are Impact Resistant Shingles Worth Installing (aka Worth the Investment)?

In general, this type of shingle is worth the investment because of the added protection and the material’s longevity. The need for impact resistant shingles, however, largely depends on where you live. In a hail-prone area like Colorado, homeowners need this type of roofing product.

Following a hailstorm, you may notice your impact resistant shingles have some minor damage and granule loss. The real value that an impact resistant shingle delivers is its design for strength in these extreme weather conditions and are much less likely to crack and for water from entering a home than traditional shingles.

As we’ve stated above, benefits of a Class 4 impact resistant shingle include savings from maintenance and repairs, premature roof replacement costs, and possible discount to your insurance premium.


Are Impact Resistant Shingles Hail Proof?

At Metro City Roofing, we tell our Denver metro customers that no roofing shingle is hail proof, but there are many options for Impact Resistant shingles. We share that an impact resistant shingle will withstand most of the hailstorms in Colorado, but not a monster hailstorm as we experienced in May 2017. On May 8, 2017, a severe hailstorm delivered 3 inch or greater sized hailstones across the Denver metro Front Range. Many roofs with Class 4 Impact Resistant shingles still had hail damage to their roofs, but they withstood the extreme damage much better than their lesser quality shingle roofs.

Local Code Requirements

Colorado cities and counties are shifting to add to their local code requirements require a Class 4 roof shingle when replacing a roof. This is happening far beyond Colorado, in states like Florida and Texas, which also receive extreme weather.

Beyond shingle requirements, local code requirements continue to advance with drip edge required at eaves and rakes and an ice barrier (often called Ice and Water Shield) required in some Denver metro cities and counties. Check out Locations page for your specific Denver metro city or county to learn more.

Many roofing companies also upgrade customers with this premium shingle. For a limited time, Metro City Roofing is offering a free upgrade to a Class 4 Impact Resistant shingle on all asphalt shingle roof replacements.

Class 4 Shingles Installation

Installing a Class 4 Impact Resistant shingle is the same as any asphalt shingle. According to the International Building Code (IBC), asphalt shingles must be fastened to solidly sheathed decks. Asphalt shingles can only be installed on roof slopes of 17% of greater (2 units vertical in 12 units horizontal). Fasteners for asphalt shingles can be galvanized, stainless steel, aluminum, or copper with no less than four fasteners per strip shingle. For areas of high wind, there may a need for additional fasteners to comply with the manufacturer’s requirements.

Beyond only a Class 4 Impact Resistant shingle, we recommend installing the matching Impact Resistant ridge cap.

Additional Types of Hail Resistant Roofing Materials

Beyond asphalt shingles, manufacturers offer different roofing materials, including metal, concrete tiles, and, more recently, a synthetic or plastic-type roofing material. Boral is a popular concrete tile, and DaVinci and F-Wave make synthetic materials. As an example, many DaVinci roofs survived without any or minimal damage in Denver’s most extreme recent hailstorm in May 2017. This hailstorm had 3 inch or greater sized hailstones – the size of baseballs.

Why Metro City Roofing?

We’re more than just an installer of a premium Class 4 Impact Resistant shingle. We are hail damage roof insurance claims experts and have perfected the roofing insurance claim and roof restoration process. We work with all the major insurance companies and manage the entire insurance claims process on your behalf. We start with a free roof inspection and represent you throughout your hail damage insurance claim process, ensuring that you receive all funds owed to you.

We are state-licensed independent adjusters, which means we evaluate your property with the same lens as an insurance adjuster.

Our goal is to simplify the hail damage claims process for you following a hailstorm, offering a full explanation of any damages and possible code-related requirements. We provide complete documentation of our inspection process, including photos and a written damage estimate, and act as a full-service claims and construction management company when a covered peril such as hail or wind requires an insurance claim.

Our expert roofers will install your new roof material with quality workmanship.

We provide the best professional roofing services in metro Denver, Fort Collins, Colorado Springs, and across the Front Range.

We continually strive to differentiate from our competitors in the following ways:

  • Licensed inspectors who inspect your roof and property with the lens of an insurance adjuster; all commercial inspections include an evaluation with an infrared camera
  • Professional insurance claims experts who settle your claim successfully
  • Expert sales representatives who help customers select the best roof for their home or business
  • Quality project managers who provide expert supervision on every roofing project
  • Experienced roof installers with many years of experience who pursue excellence with each roof replacement, restoration or roof repair
  • Long-term warranties that cover material and quality and are backed by manufacturers

Metro City Roofing offers a free upgrade to Class 4 IR shingle with every shingle roof replacement.

Contact Metro City Roofing today to schedule your free roof inspection.