October 26, 2026 · 7 min read · Materials
The short answer
A Class 4 shingle has passed the toughest impact test in the UL 2218 standard: a 2-inch steel ball dropped from 20 feet onto the same spot twice without cracking the shingle. It is a hail and impact rating, not a wind rating. In Palm Beach County, where wind is the bigger threat than hail, a Class 4 shingle makes sense when you want a tougher, more flexible shingle and are willing to pay more than a standard architectural line. It does not replace correct nailing, underlayment and flashing, which are what keep a roof on in a hurricane.
Molsbee Roofing installs Class 4 shingle lines from Owens Corning and GAF, including Owens Corning Duration FLEX and GAF's impact-resistant Timberline line. We are an Owens Corning Preferred Contractor and a GAF Certified Contractor, and we have roofed Palm Beach County homes since 1975 from our shop in Lake Worth Beach.
What does "Class 4" actually mean?
UL 2218 is the impact test most shingle makers use. Steel balls of growing size are dropped onto the shingle, and the rating is the largest ball it survives without a crack:
| Rating | Steel ball | What it tells you |
|---|---|---|
| Class 1 | 1.25 inch | Basic impact resistance |
| Class 2 | 1.5 inch | Moderate |
| Class 3 | 1.75 inch | High |
| Class 4 | 2 inch | Highest rating in the standard |
Class 4 lines are usually made with a rubber-like (SBS-modified) asphalt that bends under a hit instead of cracking. That flexibility is the real difference you are paying for.
Class 4 is not a wind rating
This is the most common mix-up we hear. A shingle's wind rating comes from different tests, and the number that matters for a Palm Beach County roof is the design wind speed for your address: about 150 mph inland and up to 170 mph on the barrier islands. Any shingle we install, Class 4 or not, is nailed to the manufacturer's high-wind pattern and built to the Florida Building Code for your wind band.
So a Class 4 shingle is a tougher shingle. It is not, by itself, a more wind-proof roof. The wind performance comes from the whole system: deck, secondary water barrier, nailing, edge metal and flashing.
Do Class 4 shingles make sense here?
Hail does fall in Palm Beach County, mostly in spring and summer thunderstorms, but it is less common than in the middle of the country where Class 4 shingles first caught on. The better reasons to choose one here are:
- Flying debris. Branches, palm fronds and loose objects hit roofs in strong storms. A flexible shingle takes those hits better.
- Heat. SBS-modified shingles stay flexible longer, which helps a roof that bakes in the sun most of the year.
- Peace of mind on a long stay. If you plan to keep the home, the extra toughness is easier to justify.
Some owners also ask their agent whether a Class 4 roof changes anything on their policy. That depends on the carrier, so ask before you count on it.
Class 4 vs standard architectural shingles
| Standard architectural | Class 4 impact-resistant | |
|---|---|---|
| Upfront cost | Lower | Higher |
| Impact rating | Usually not rated, or lower class | Highest class in UL 2218 |
| Flexibility | Stiffer as it ages | Stays more flexible |
| Wind performance | Set by nailing and code-built system | Same: set by nailing and code-built system |
| Lifespan in Palm Beach County | Generally 13 to 18 years | Generally 13 to 18 years |
| Colors | Widest range | Good range; we confirm each color with our supplier |
What changes the price
We do not publish a price chart, because two homes of the same size can land far apart. A Class 4 line costs more than a standard architectural shingle, but the shingle is only one part of the price. The rest is the same as any shingle roof:
- Roof size, pitch, hips, valleys and penetrations
- Tear-off and disposal of the old roof
- Deck repair, priced as a unit rate once the deck is exposed
- Secondary water barrier, ventilation, flashing and edge metal
- Permit and inspections, which we file and schedule
Our guide to shingle roof replacement cost in Palm Beach County walks through each of those lines.
Picking a color
Class 4 lines come in most of the popular shades. Lighter colors reflect more of the afternoon sun, and your HOA may keep an approved list. Our Owens Corning color guide covers how to narrow it down.
Should you consider metal instead?
If impact and long life are what you want most, metal is worth a look too. It costs more up front and generally lasts 20 to 25 years here. Our metal roof vs shingles comparison lays out the trade.
See shingle roofs in your town
Read about shingle roof replacement in West Palm Beach, Boca Raton, Delray Beach, Jupiter and Wellington, or see our shingle roofs page.
Next step
Call (561) 318-8624 or request a free roof inspection. We will price a standard shingle and a Class 4 shingle for your roof, in writing, so you can compare them side by side before you decide.
