If you’ve been shopping for metal roofing or talking to contractors, you’ve probably heard someone throw out “Class 4 impact rated” like it explains itself. It doesn’t. Most homeowners have no idea what it means, and honestly, a lot of contractors can’t explain it either.
Here’s the full breakdown — what the rating is, how panels earn it, and why it matters for your wallet and your roof.
The Rating Comes From Underwriters Laboratories (UL)
Underwriters Laboratories — UL — is an independent, nonprofit testing organization that’s been evaluating product safety for over a century. When it comes to roofing, they developed a standard called UL 2218, which rates how well a roofing material holds up under impact.
The scale runs from Class 1 (lowest) to Class 4 (highest). Class 4 is the toughest impact rating available for roofing materials.
How the Test Works
The test is exactly what it sounds like: they drop steel balls onto roofing material from a specified height and see what happens.
Each class corresponds to a different ball size:
| Class | Steel Ball Diameter |
|---|---|
| 1 | 1.25 inches |
| 2 | 1.50 inches |
| 3 | 1.75 inches |
| 4 | 2.00 inches |
To earn a Class 4 rating, a panel must take a 2-inch steel ball dropped from 20 feet — twice, in the same spot — with no cracking, tearing, splitting, or fracturing. The test is also performed at the most vulnerable points of the panel: edges, corners, unsupported sections, and joints.
If it shows any damage, it fails.
A 2-inch steel ball at that drop height is simulating a 2-inch hailstone traveling at terminal velocity. That’s a significant impact — and Class 4 panels take it without flinching.
Why It Matters for Homeowners
1. Indiana is in hail country
Indiana is consistently listed among the most hail-prone states in the country. A standard asphalt shingle roof can crack, split, and granulate under a hailstorm. Once that happens, you’re looking at water infiltration, interior damage, and a roof that’s aged years in a single storm event — even if it doesn’t look destroyed from the ground.
A Class 4 steel panel is engineered specifically to survive that scenario. The material doesn’t crack or puncture. At worst, you might see a minor cosmetic dent. That’s a completely different outcome.
2. Your insurance company will reward you for it
This is the one that surprises most people. Multiple major carriers — including State Farm and Indiana Farm Bureau — offer premium discounts specifically for homes with Class 3 or Class 4 impact-rated roofs. Indiana is explicitly listed by State Farm as a qualifying state for this discount.
Insurance discounts for Class 4 roofs typically range from 10% to 30% depending on your carrier and location. On a $1,500 annual premium, that’s $150 to $450 back in your pocket every single year — for the life of the roof.
The math matters: a steel roof that lasts 40–50 years, delivering insurance savings annually, closes the cost gap against cheaper materials faster than most people expect.
What you need to qualify: Ask your insurance agent if they have a specific form your contractor needs to fill out confirming the UL 2218 Class 4 rating on the specific panel installed.
3. It reduces your exposure on hail deductibles
Here’s the part most homeowners don’t realize until it’s too late: many policies in hail-prone states now carry separate wind/hail deductibles that run 1% to 5% of your home’s insured value. On a $300,000 home, that’s $3,000 to $15,000 out of pocket before insurance kicks in — per event.
A Class 4 roof dramatically reduces the odds you ever have to write that check.
4. Fewer claims, longer roof life
A roof that survives hail without damage is a roof that doesn’t need emergency repairs, tarps, or premature replacement. Metal roofs are already rated for 40–70 years. Combined with a Class 4 impact rating, you’re looking at a roofing system that may genuinely outlast your ownership of the home.
Why It Matters for Contractors
If you’re installing roofs for a living, here’s what you need to know:
Documentation protects you and your customer. When you install a Class 4 rated panel, provide your customer with the product literature and a written record of what was installed. That paper trail is what gets them the insurance discount. It also protects you if there’s ever a question about the installation.
It’s a real selling point. For homeowners in Indiana, a contractor who understands the UL 2218 rating and can speak to insurance savings is going to stand out from one who just says “it’s metal, it’s tough.” Know the spec and use it.
Indiana Metal’s Steel Panels Are Class 4 Rated
All our panels carry the UL 2218 Class 4 impact rating. If you’re a homeowner evaluating a metal roof — or a contractor quoting one — we can provide the product documentation you need for insurance certification.
Questions? Call us, email us or stop into one of our locations. We’ll help you get the information you need.
Jena Jackson, Marketing Indiana Metal Inc
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