Is Your Roof Impact Resistant? | Determining Roof Strength

Do you know anyone who enjoys replacing or repairing their roof? The answer to that is probably no one. For one, it costs a lot of time and money to fix roofs due to damage and natural wear and tear. It’s normal for roofs to age and to become damaged and deteriorate. The main reason your roof experiences damage and wearing are weather conditions.

Not all roofs are created equal. Some are stronger than others and better protect roofs against damage.If you’ve wondered how durable your roof is, it depends on the type of roofing materials used when the roofing installation company installed it. There are many roofing materials, but the only type guaranteed to be impact resistant is category 4 roofs. These are also called impact-resistant shingles or hail-resistant shingles.

This article is provided by our team of expert roofers. We provide services for roofing Worcester MA. Reach out for any questions or concerns!

What Kind of Damage Can Hail Do?


From 2000-2019 hail damage averaged between 8-$14 billion per year. In 2020 alone, State Farm paid out over $3.1 billion. Texas, South Dakota, Kansas, Oklahoma, and Missouri are most at risk for hail damage.

Hail is formed when high winds propel raindrops upward into colder areas. While falling back down, they become larger when combined with water drops. How they mix with the raindrops determines if they become larger or create a new hail ball. Believe it, or not some hail balls are so large and fall so fast they can rip the siding off a house, break windows, and even cause severe injury or death.

While hail doesn’t seem like it would be very damaging, as you read above, it can cause a lot of damage and be incredibly dangerous. While no roofing material, regardless of the class, can protect your roof a hundred percent, a class 4 roof can help prevent more damage than other classes.

What Can Hail Do To Your Roof?

Like all extreme weather, the amount of damage hail does to your roof depends on where you live. In some areas, hail will melt before hitting the ground where people barely see an icicle, whereas, in other places, it can grow to the size of small rocks or even golf balls. Whether it’s the size of a small stone or a golf ball, there will be some type of damage caused by the hail. At first, the damage may not be noticeable, but it will become worse and weaken your roof over time.

Here is what happens when hail hits the roof:

  • Granule loss – these are the sandpaper-like particle on the top of the shingle. As the roof ages, these come off gradually, but with hailstorms, they will knock them off quickly, causing your roof to start deteriorating.
  • Cracks in shingles – this may lead to tears, leaving your roof with bare spots. These bare spots and cracks are the perfect place for rain, snow, and ice to start settling.
  • Exposed fiberglass mat – if the hail shatters the shingle, it will cause the mat underneath, leaving your home vulnerable to damage.

Which Shingles Are The Most Impact Resistant?


Roofs come in 4 different classes. Each class is tested and then put in the appropriate category based on how much impact they can take before the top layer cracks. Class 4 roofs are the most impact-resistant and could withstand a 2” steel ball dropped from the height of 20ft—kinetic energy of 23.71 ft:lbf at the time of impact. Below you’ll find the results of each of the different classes on the test.

  • Class 1 did not crack when hit twice in the same spot by a steel ball 1.25” in diameter.
  • Class 2 didn’t crack when hit twice in the same spot by a steel ball 1.50” in diameter.
  • Class 3 didn’t crack when hit twice in the same spot by a steel ball 1.75” in diameter.
  • Class 4 didn’t crack when hit twice in the same spot by a steel ball 2.00” in diameter.

Above, you can see shingles that are damaged easier get a lower rating by the UL 2218 Impact rating tests.

Are Class 3 Roofs Impact Resistant?

While class 3 roofs are better than either class 1 or 2, they are not impact-resistant. The only roofs that are considered impact resistant are class 4. This means that these roofs met the UL 2218 requirements. They are manufactured with rubberized asphalt creating a more flexible crack-resistant roof.

What Other Roof Types Are Impact Resistant?


Class 4 shingles aren’t the only type of highly durable, impact-resistant roof. Asphalt shingles aren’t the only roofing material with a class 4 rating. The ones listed below are also excellent choices.

  • Metal – A metal roof has a lot of benefits, including its energy efficiency. They are also wind resistant, fire-resistant, and an excellent choice for individuals looking for an eco-friendly and recyclable option.
  • Clay Tile – Clay tiles are beautiful and can last up to 100 years. You want to make sure that they have excellent drain systems to reduce the risk of water damage.
  • Wood Shake – these shingles are thicker than typical wood shingles and are a natural insulator. These shingles can easily last up to 40 years if properly taken care of.
  • Slate – these roofs are most popular on historic buildings. They are highly durable and are also impact resistant when cut to the proper thickness. You’ll have to make sure that the slate is cut ⅝” to be considered impact resistant.
  • TPO – these are rubberized slate shingles, so basically rubber shingles that look like slate ones. These shingles have a natural bounce similar to asphalt ones. They come with a 50-year warranty with a life expectancy of 100 years when properly maintained.

Do You Need An Impact Resistant Roof?

This is something for you and your certified roofing specialist to discuss. While we recommend getting at the minimum a class 3 roof, you need to consider a few things. First and foremost is your budget. Class 4 roofs will save you money in the long run but are more expensive than class 3 roofs.