Standards
FORTIFIED Roof vs a Class 4 Shingle
One is a product rating. The other is a verified roof system. Why the difference decides grants, insurance credits and whether the roof stays on.
Facts checked October 8, 2026
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Two very different claims
A roofer tells you the new shingles are "Class 4" or "hurricane rated." Another says the roof will be "FORTIFIED." Both sound like the same promise. They are not.
- Class 4 is an impact-resistance rating for a product. It tells you how a shingle performed when struck in a laboratory test.
- FORTIFIED is an IBHS standard for the whole roof system — how it is attached, sealed, edged and finished — verified by an independent evaluator and designated by IBHS.
A Class 4 shingle can be part of a FORTIFIED roof. It cannot make a roof FORTIFIED on its own.
What wind actually does to a roof
Hurricanes rarely beat a roof by punching holes in shingles. They win at the weak points:
- Edges and corners, where uplift is strongest, peel back first.
- Roof decking that is under-nailed can lift off the trusses.
- Rain pours through the gaps between deck panels once the covering is gone.
FORTIFIED addresses each one: stronger deck attachment, a sealed roof deck so water stays out even if shingles blow off, reinforced drip edge and starter details at the edges, and properly fastened flashing and vents. None of that is visible once the roof is finished — which is why it must be documented while the roof is open.
Why verification matters
Any contractor can say a roof was built right. A FORTIFIED designation requires proof:
- An IBHS-certified FORTIFIED evaluator — independent of the roofer — documents the critical stages, before each layer is covered.
- IBHS reviews the evidence and issues the designation, which lasts five years.
That paper trail is what grant programs and insurers rely on. In South Carolina, the largest SC Safe Home award requires it. In North Carolina, Strengthen Your Roof does too.
Product rating vs system designation
| Class 4 shingle | FORTIFIED Roof | |
|---|---|---|
| What is rated | One product | The whole installed roof |
| Who decides | The manufacturer's lab test | An independent evaluator and IBHS |
| Covers deck attachment | No | Yes |
| Covers a sealed roof deck | No | Yes |
| Covers edges and flashing | No | Yes |
| Proof you can hand an insurer | A product spec sheet | An IBHS designation certificate |
| Qualifies for FORTIFIED grants | No | Yes, with the program's other requirements |
So should you buy Class 4 shingles?
They can be a good choice, especially where hail is a concern, and some insurers credit impact-rated roofs separately. Just don't let a shingle label stand in for the system. If your goal is a grant, an insurance credit tied to FORTIFIED, or simply a roof that stays on, ask for a FORTIFIED installation and an independent evaluator before the tear-off.
We place homeowners with licensed, certified and insured FORTIFIED evaluators along the North and South Carolina coast.
Keep reading
Planning a FORTIFIED Roof?
We place you with a licensed, certified and insured FORTIFIED evaluator who documents the roof for IBHS — the record a Resilient Mitigation grant and most insurance credits rely on.
Related reading
North Carolina vs South Carolina FORTIFIED Roof Grants
Strengthen Your Roof vs SC Safe Home: who runs each grant, what it pays and what's the same in both states.
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Six things to do now so you can apply on day one of the next round.
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