Are you trying to pick a shingle? Do you keep coming across class 3 or class 4 when researching and/or talking to a roofing contractor about specific shingles?
I’m sure seeing or hearing a shingle has “class” is confusing enough, but there are also different levels to these ratings. This isn’t just something slapped on a shingle to identify it.
The classification is actually determined by 3rd-party testing. And because of what it tests, a shingle’s class should always be considered when making a decision.
So, what do the shingle classes mean? And what’s the difference between class 3 and class 4 shingles?
For over 30 years, Bill Ragan Roofing has simplified the technical and complex information homeowners need to choose the right roofing material. That’s why I’ll help you understand shingle classifications and the differences between them.
By the end of this article, you’ll have the answers to the following questions:
- What do shingle classes mean?
- What’s the difference between class 3 and class 4 shingles?
- What makes class 4 shingles more impact-resistant than class 3 shingles?
- Do class 4 shingles cost more than class 3 shingles?
- Are class 4 shingles worth it?
What do shingle classes mean?
A shingle’s classification is the impact-resistance rating for its ability to withstand hail or other impacts. Impact ratings go from 1 to 4, with each class representing the size of hail a shingle can handle without getting damaged.
The classification is determined through Factory Mutual (FM) or Underwriters Laboratories (UL) by testing a shingle's ability to withstand an impact from 20 feet. They do the test the same way, but UL uses steel balls, while FM uses ice balls that are denser and harder than most hailstones.
The size of the steel or ice ball a shingle can handle without damage is what determines the classification.
What’s the difference between class 3 and class 4 shingles?
The difference between class 3 and class 4 shingles is simply that class 4 can handle larger impacts. However, to truly understand the difference, you need to know the rating system.
Below are the Classifications for both UL and FM impact ratings:
- Class 1 shingles can withstand steel/ice balls that are 1.25” in diameter.
- Class 2 shingles can withstand steel/ice balls that are 1.5” in diameter.
- Class 3 shingles can withstand steel/ice balls that are 1.75” in diameter.
- Class 4 shingles can withstand steel/ice balls that are 2” in diameter.
As you can see, the actual difference is that a class 3 shingle can handle 1.75” hail while class 4 can handle 2” hail. While class 4 is the highest impact rating a shingle can have, class 3 is still very durable.
Just know these tests can’t 100% replicate shingle performance due to factors like temperature, shingle age, and impact angle. So, it’s still possible for hail to damage any shingle class if the conditions are right.
What makes class 4 shingles more impact-resistant than class 3 shingles?
Some class 4 shingles are stronger simply because they’re thicker, have a multi-layer design, or come on a reinforced mat. However, manufacturers also utilize specialized materials/formulas to make shingles impact-resistant.
One way is by adding a polymer-modified mesh to shingles that holds them together instead of splitting when hail or another object hits. This method absorbs the impact, which can end up weakening with frequent or continuous hail storms.
The other way is adding a rubber-type polymer (mainly styrene-butadiene-styrene aka SBS) to the asphalt shingles. Adding SBS or another rubber-like polymer creates more flexibility, which allows the hail to bounce off the shingles instead of absorbing the impact.
No matter the reason, getting a class 4 impact-resistance rating means the shingle passed strong testing. But just know the shingles passed at the time of manufacturing, so they become less resistant as they age.
Do class 4 shingles cost more than class 3 shingles?
Impact-resistant shingles are considered performance shingles, and some even only come in designer or luxury lines. Because of this, most class 4 shingles are more expensive than class 3 or other traditional asphalt shingles.
There’s not a huge cost difference between a class 3 and class 4 architectural asphalt shingle. However, some luxury shingles are class 3.
So, a class 3 luxury shingle compared to a class 4 architectural shingle is the one exception where class 3 costs more. Even if they have the same rating, a luxury shingle will be around double the cost of architectural shingles.
Unfortunately, pricing heavily depends on the type of shingle, manufacturer, and your area. So, I can’t be exact about the cost differences.
Are class 4 shingles worth it?
The roofing industry is replacing roofs at a record pace right now as damaging storms become more frequent in the United States. In my opinion, Class 4 impact-resistant shingles are worth the initial high investment.
Most insurance companies offer policy discounts for Class 4 shingles, and the changes coming to the insurance industry make it more important than ever to have a roof with strong storm damage resistance. In fact, some areas require Class 4 impact-resistant shingles on new roofs per local building codes for this exact reason.
However, they’re also worth it for the increased durability. Meeting the high-quality standards to qualify for a class 4 rating doesn’t just make them impact-resistant, but it generally makes them more durable and helps them last longer.
What are the best class 4 impact-resistant shingles?
After reading this article, you know how shingles get their class, the difference between the classes, and what class 4 shingles are more impact-resistant than class 3 shingles.
While class 4 shingles are more expensive, they’re well worth it for durability and insurance purposes. Just remember to look at your local codes to determine if class 4 shingles are actually required in your area.
Whether they’re required or you simply want their benefits, you still need to pick a specific shingle. That’s why you need to know the best class 4 shingles available in the roofing industry right now.
Check out The 5 Best Class 4 Impact-Resistant Shingles to learn the top options for homeowners who need or want an impact-resistant shingle.
