How Hail Damages a Roof
Of all home areas, your roof is most at risk for hail damage. Asphalt shingles impacted by hail can loosen and shed the protective granules that coat their surface. Wood shake, clay tile, and other types of natural roofing can split or crack. Some hail damage isn’t obvious: seemingly insignificant impacts can still cause harm to underlying roof structures. When shingles become bruised by hail, micro fractures at the point of impact allow water to seep through. The sun’s ultraviolet light can weaken exposed bruised spots and make them brittle. Extreme temperature swings are also worrisome. They can cause the rapid expanding and contracting of roofing materials, which can weaken shingles and exacerbate hail damage.
To combat problems caused by hail, contractors turn to impact resistant (IR) roofing. The UL 2218 classification – developed in 1996 by the Institute of Business and Home Safety and Underwriters Laboratories – is the national standard for roof impact resistance. Roofing materials receive an IR rating of 1-4 (four being the strongest) based on a laboratory test in which a steel ball is dropped onto the materials from a certain distance.
When it comes to asphalt shingles, many types of IR products available. Polymer-modified (a.k.a. rubberized) shingles are a great option. The flexibility of the polymers that are blended with the asphalt means these shingles better handle the force of impact than non-modified shingles. They are also more resistant to damage from extreme temperature changes. If you live in an area susceptible to hailstorms, IR shingles are worth investing in – you may even get a homeowners insurance discount for having these highly durable shingles installed on your property.
Watch our video - NorthGate impact-resistant shingles vs. standard asphalt shingles
Protecting Your Home From Hail Damage
An ideal way to protect your home from hail: invest in impact-resistant roofing products like rubberized shingles . If a hailstorm is headed your way, there are important steps you should take to protect your property. Move fragile and detached elements like pottery, plants, and lawn furniture inside. Park your car in a covered area. Close your curtains and, most importantly, stay inside.
Inspect your roof after every storm. If you’re not sure how much damage there is, check your gutters for collected asphalt granules. If you see a large accumulation of granules after hail, you should have your roof inspected by a professional. Also, check to see if objects like roof vents have sustained heavy damage. The harm dealt to these items is an indicator to the degree of roof damage.
If the roof is severely damaged and needs support before it can be repaired, FEMA may be able to provide a tarp to protect you from the elements1. They can be reached at 1-888-766-3258.
Read More: Impact-Resistant Shingles May Save Your Home
Hailstorms Have Always Been a Nuisance
Throughout history, people have tried to find ways to prevent roof hail damage, as well as the havoc hailstorms wreak on crops, livestock, and humans. In 1360, during the Hundred Years’ War2, a French hailstorm killed hundreds of invading English soldiers, causing King Edward III to give up his conquest.
According to National Geographic, Europeans in the 18th century tried to prevent hail by ringing church bells and firing cannons into the clouds. In the 20th century, Russia and the United States tried “cloud seeding,” where chemicals were dispersed from rockets or aircraft in an attempt to control rain and hail. This process was never proven to be effective. Today, hail and wind damage make up 38 percent3 of all homeowner insurance claims.
Destructive hailstorms are increasing in the United States, with hail now costing the U.S. as much as $22 billion a year in damage to homes, cars, crops, and people4. Additionally, hailstorms account for 70 percent of insured losses from severe storms5. A dime-sized hailstone falls at 20 miles per hour, while a three-inch, baseball-sized one can reach between 80 and 110 mph. At these velocities, hail can inflict significant damage on homes that lack impact-resistant roofing materials.
The Science Behind Hailstorms
Hailstorms are typically a byproduct of severe thunderstorms. Hailstones form when raindrops are carried upward and freeze in the extremely cold atmosphere; they continue to grow as they collide with water droplets that freeze onto the hailstone’s surface.
Hail falls when the updraft can no longer support the weight of the hailstone. Most hail falls at speeds between 25-40 miles per hour, but very large hailstones (diameters exceeding four inches) can fall at speeds of more than 100 mph. In the U.S., these storms occur most often in Hail Alley – a region composed of the Great Plains states of Texas, Oklahoma, Kansas, Nebraska, Colorado, Wyoming, Montana, and the Dakotas. States in this region experience hail impacts seven-to-nine days a year6.
Hail swaths (paths of hail) can range in length from a few to 100 acres. Whether large or small in size, hail can cause serious damage. According to the U.S. Department of Commerce, hailstorms caused $723 million in property damage and $87 million in crop damage in 2018 alone7.
Sources:
1. https://www.fema.gov/news-release/2004/10/02/operation-blue-roof
2. https://www.history.com/this-day-in-history/hail-kills-english-troops
3. https://www.kin.com/blog/most-common-home-insurance-claims
4. https://www.cbsnews.com/news/hail-damage-costs-this-year-could-hit-new-annual-high-in-u-s/
5. https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/08/08/
6. https://www.nssl.noaa.gov/education/svrwx101/hail/
7. https://www.iii.org/fact-statistic/facts-statistics-hail
