Emerging Research and Impact-Resistant Roofing

Minnesotans are no stranger to severe weather. Whether it’s snow, hail, rain, or wind, our roofs take a beating. After a brutal winter, we are now entering the rain and storm season, which means hail and tornadoes.

Hail is a peril that threatens all but a handful of states in the United States, but it doesn’t strike all areas equally. Since 1980, the country has averaged 3,000 hailstorms a year.  Officials estimate that up to 40 percent of all homeowners insurance claims result from hail damage. While the Midwest and Great Plains states have the most hailstorms, Colorado has the most storms with large-size hail (diameter greater than 1.5 inches). So even though Colorado has fewer storms, the storms that occur cause more damage.

Impact Resistant Roofing

Lost in these large numbers is the number of repeat claims — resulting in payments to the same customers for the same type of repairs from the same type of hailstorms. There are some areas of the nation’s hail belt where homes have been reshingled two and three times during a 10-year period.

While a hailstorm usually strikes a relatively limited geographical area, there are parts of Texas, Oklahoma, Kansas and Nebraska where hailstorms average six strikes a year or more. Clearly, the same houses are exposed to these storms. They are likely to receive damage.

As a result, home insurance coverage in these regions has become expensive. As premiums rise, both insurers and their policyholders become concerned.

To help combat rising premiums, insurance companies look for ways to prevent future damage. They also look for ways to limit the amount of damage when losses occur.

Customers often look to lower their premiums — often by raising their deductibles (the amount the customer pays for each claim). That can reduce the customer’s insurance bill, but it also reduces the amount of the claim payment. The customer pays the deductible.

A better course — because of its long-term implications — is damage prevention and reduction. Prevention means eliminating the cause of loss — not practical when it comes to hailstorms and roofs. Reduction means minimizing damage when a loss occurs.

For hailstorms, insurers believe the best way to minimize damage is use of roofing materials that better resist hail damage. Breakthroughs in technology and standardized testing are contributing new materials expected to more effectively resist hail damage.

How Do You Define an Impact Resistant Roof?

What kind of test will provide consumers with credible information upon which to make buying decisions? How much resistance do roofing materials lose as they age?

Despite research conducted over a number of years, it wasn’t until 1996 that a testing standard (UL 2218) was developed to grade the impact resistance of roofing materials. This was a joint effort by the State Farm-supported Institute for Business and Home Safety (IBHS) and Underwriters Laboratories, Inc. (UL). The test uses four sizes of steel balls, ranging from one-and-one-quarter inches to two inches in diameter, to replicate four sizes of hailstones. These balls are dropped from various heights to replicate various speeds of impact. Damage is measured on a scale of 1 (least resistant) to 4 (most resistant).

Choosing The Right Roofing Material

Educate yourself about the different roofing materials and select the material that suits your taste and addresses your hail, high wind and fire risks.

Choosing materials

• Asphalt shingles (reinforced with fiberglass):
  • Relatively low cost and easy to install.
  • Good fire resistance (usually Class A).
  • Class 3 and 4 impact resistance is available, should be used in hail regions.
  • Available with wind warranties up to 130 mph, if installed in accordance with manufacturer’s high wind requirements.
• Metal
  • Long life
  • Lightweight
  • Popular for low and steep-slope roofs
  • Often receives cosmetic damage from hailstorms, but Class 4 product rated for impact resistance are available.
  • Product available with Class A fire rating.
• Slate
  • Quarried in the Northeast and Virginia
  • Very strong
  • High quality slate can outlast most other roofing material
  • Requires special skill and experience for installation, which can affect cost.
  • Heavy so your contractor should verify the structure can hold the weight if you are replacing another kind of roofing material.
• Tile
  • Good in dry climates.
  • Solid, long lasting product.
  • Higher threshold for hail damage.
  • Can be more permeable than other products if exposed to blowing rain.
  • Heavy so your contractor should verify the structure can hold the weight if you are replacing another kind of roofing material.
• Wood
  • Good in dry climates.
  • Thinner products can be susceptible to hail damage, especially after aging.
  • Some building codes limit use because of wildfire concerns, but some product can be Class A fire rated with factory applied fire-resistant treatment.
  • Often used in wrong climates for cosmetic reasons.

When choosing impact-resistant roofing for the hail risk in your area:

• Look for materials rated UL 2218 or FM 4473, which indicates they have been tested and found to stand up to hail damage.
• Find out about your local building codes and what is required.
• Homeowners may be able to obtain a discount in their home insurance premiums based on roofing materials. In some states/provinces, use of qualifying impact-resistant roofing products may qualify for significant premium discounts. Premium reductions are not available for roofs, other than qualifying metal roofs, that have been overlaid onto existing roofs.

A cost-saving technology for insurers and policyholders

Approved Impact Resistant Roofing Products

To certify your eligibility, print and complete the appropriate certification form:
Roofing Installation Information and Certification Form (PDF 66 KB)

Of course, the choice of roofing materials used on your home is up to you. It’s always a good idea to discuss roof safety and impact resistance with a reliable Minnesota roofing contractor.