Head-to-Head Comparison
Class 4 vs Standard Shingles
Class 4 impact-resistant shingles cost roughly $2–$3.50/sqft more than their standard equivalents in St. Louis — but the 20–30% MO/IL insurance premium discount often turns that into a net positive within 5–8 years. This page explains the math, the qualifying products, and the claims you should know about.
Our Verdict
For virtually every St. Louis homeowner replacing a roof, upgrading to Class 4 impact-resistant shingles is financially rational when the MO/IL insurance discount is factored in. The $1,500–$3,000 upgrade cost on a typical roof pays back in premium savings within 5–8 years, with the discount continuing for the life of the roof.
| Dimension | Multiple (GAF, OC, CertainTeed) | Multiple (GAF, OC, CertainTeed) |
|---|---|---|
| Installed Cost (STL 2026) | $9.50–$14/sqft Class 4 shingles carry a $2–$3.50/sqft premium. On a 25-square roof, that's $5,000–$8,750 more — meaningful upfront, but offset by insurance savings. | $7–$10.50/sqft |
| Impact Rating | UL 2218 Class 4 (survives 2-inch steel ball at 17 ft/sec, twice) Class 4 shingles pass a significantly more demanding impact test. The difference in real-world hail resistance is measurable: Class 4 products sustain 1.75-inch hailstone impacts without breaching the waterproofing layer. | UL 2218 Class 1–2 (standard) |
| Insurance Premium Impact | 20–30% discount on wind/hail portion (MO/IL eligible) Both Missouri and Illinois allow insurers to offer premium discounts for Class 4 roofing. On a $1,800 annual policy, that's $360–$540/year in savings — $3,600–$5,400 over 10 years. | No discount |
| Storm Claim Frequency | Significantly reduced claim likelihood after moderate hail The practical difference matters beyond premium: fewer claims means lower risk of policy non-renewal or rate hikes that insurers apply after hail claims in the St. Louis market. | Standard asphalt vulnerable to 1-inch+ hail damage |
| Appearance | Identical to standard — same visual profiles available Class 4 versions of GAF, OC, and CertainTeed flagship lines are visually indistinguishable from their standard counterparts. No aesthetic tradeoff. | Full range of standard options |
Choose Multiple (GAF, OC, CertainTeed) if...
Choose Class 4 impact-resistant shingles for almost any St. Louis full roof replacement — the MO/IL insurance discount almost always produces positive ROI within 5–8 years, with no visual tradeoff.
Choose Multiple (GAF, OC, CertainTeed) if...
Standard architectural shingles make sense only when budget is the primary constraint and the insurance discount can't be accessed (e.g., rental property with commercial coverage, or carrier that doesn't offer the discount).
The UL 2218 Test Explained
UL 2218 is the industry's standard for impact resistance in roofing materials. The test fires a steel ball (simulating hailstones) at roof samples from a fixed height and measures whether the impact creates a crack in the underlying felt layer. Class ratings 1–4 correspond to increasing steel ball diameters: Class 1 (1.25 inches), Class 2 (1.5 inches), Class 3 (1.75 inches), Class 4 (2 inches). Each test is run twice on the same spot — twice without breach qualifies the product for that class.
Class 4 is the highest standard and correlates roughly to surviving 1.75-inch real hailstones without breaching the waterproofing layer. In practical terms, a hailstorm that would require replacement of a Class 1–2 roof might leave a Class 4 roof with minor granule loss but no structural damage. This is the core reason insurers are willing to discount: fewer claims.
One important caveat: UL 2218 tests impact resistance of the shingle itself, not the total system. Improper installation — too few nails, wrong nail placement, insufficient starter course — can cause wind and water infiltration that bypasses the shingle's impact performance entirely. Class 4 shingles improperly installed still fail.
Missouri and Illinois Insurance Discount Law
Both Missouri and Illinois have adopted statutes allowing (not mandating) insurers to discount premiums for homes with qualifying impact-resistant roofing materials. Missouri's law (RSMo 379.706) and Illinois's equivalent authorize carriers to reduce the wind/hail portion of homeowner premiums by up to 30% for Class 4 roofs.
In practice, discounts vary by carrier and policy structure. State Farm, Farmers, Shelter Insurance, and Allstate all offer the discount in the St. Louis metro. USAA applies it to qualifying properties. The wind/hail portion of a typical St. Louis homeowner policy runs $800–$1,800 annually depending on home value and coverage level — the 20–30% reduction on that portion translates to $160–$540/year in most cases.
The process to claim the discount: obtain a UL 2218 Class 4 certificate from your installer (this should be provided automatically; ask if it isn't), then submit it to your insurer with a completed roof upgrade form. Most carriers apply the adjustment within 30–60 days. Revolve provides the necessary documentation on every Class 4 installation.
Which Class 4 Products Are Available in St. Louis
All three major manufacturers offer Class 4 versions of their flagship architectural lines. GAF's Timberline HDZ CS (Cool Series) and StainGuard CS carry Class 4 ratings. Owens Corning Duration Storm is the OC Class 4 flagship. CertainTeed Landmark IR is CertainTeed's Class 4 offering. All are widely distributed in St. Louis through SRS, ABC Supply, and Beacon.
Beyond standard asphalt, all standing seam metal roofing (24–26 gauge), DaVinci and Brava synthetic slate, and stone-coated steel products carry Class 4 ratings as baseline properties — not upgrades. If you're considering any of those materials, the insurance discount applies automatically.
One product category that qualifies but is sometimes overlooked: impact-resistant designer shingles. CertainTeed's Grand Manor IR and GAF's Camelot II IR carry Class 4 ratings and are in the designer tier ($11–$14/sqft installed). These are worth considering for high-visibility roofs where visual differentiation from standard architectural shingles matters.
St. Louis Context
St. Louis is in one of the most active hail corridors in the US. MO and IL both authorize 20–30% premium discounts for Class 4 roofing — and the frequency of claims in the metro means insurers here apply the discount broadly. Upgrading to Class 4 on a full roof replacement is one of the highest-ROI home improvement decisions available to St. Louis homeowners.
Frequently Asked Questions
How much will I actually save on insurance with Class 4 shingles?+
The MO/IL discount applies to the wind/hail portion of your premium, which typically represents 40–60% of total homeowner insurance cost. A 25% discount on that portion of a $1,800 policy saves roughly $180–$270/year. On a premium-heavy policy (older home, high-value home, aggressive hail history), savings can reach $400–$600/year. Call your insurer before the installation for a pre-commitment estimate — they'll give you a number.
Does every insurer in Missouri offer the discount?+
No — the law authorizes discounts, it doesn't mandate them. Most major carriers in St. Louis do offer it (State Farm, Shelter, Farmers, Allstate, USAA). Some smaller carriers or specialty markets don't. Check your specific policy. If your current carrier doesn't offer the discount, it's worth shopping — carriers that offer Class 4 discounts are often more competitive on overall homeowner rates in hail-risk markets.
Can I get a Class 4 discount if I had storm damage repaired — not a full replacement?+
Generally no. Most carriers require a full roof replacement with qualifying Class 4 material to apply the discount. A partial repair, even with Class 4 shingles, typically doesn't qualify because the remaining original shingles are still Class 1–2. Confirm with your insurer before committing to a partial repair vs. full replacement decision.
Does a Class 4 roof mean my insurer can't raise my rates after a hailstorm?+
No. Class 4 shingles reduce claim frequency (fewer claims because less damage), but your insurer can still raise rates in response to area-wide hail events regardless of your roof type. The real benefit is claim avoidance — fewer claims means less risk of non-renewal and fewer instances of individual rate adjustment.
Is there any visual difference between Class 4 and standard architectural shingles?+
No. Class 4 versions of GAF, OC, and CertainTeed products look identical to their standard counterparts. The impact resistance comes from SBS rubber-modified asphalt in the manufacturing process, not from any visible feature. Color selection, texture, and architectural profile are all the same.