Minnesota saw hail of 1.5 inches or larger on multiple days this summer, from St. Cloud on July 4 to Park Rapids and Vesta in August. Meanwhile, Wisconsin insurers now report hail as the single most common homeowners claim. Against that backdrop, Class 4 impact resistant shingles have become one of the most frequent questions on our estimates. What does the rating mean? How much more do they cost? Will your insurer reward you for installing them? Below, we give a straight answer to each in turn.
What Class 4 impact resistant shingles actually are
To begin with, the rating comes from a laboratory test called UL 2218. Technicians drop steel balls of increasing size onto a shingle sample from a set height. Afterward, they inspect the back of the shingle for cracks or tears. For instance, Class 1 survives a 1.25-inch ball. Class 4, the highest rating, survives a 2-inch steel ball dropped from 20 feet, twice in the same spot. The back of the shingle must show no fracture.
A 2-inch steel ball hits harder than a 2-inch hailstone, so the test is deliberately conservative. Manufacturers reach the rating by reinforcing the shingle. Usually that means a polymer-modified asphalt that stays flexible, or a fiberglass mesh laminated to the back. GAF, Owens Corning, and CertainTeed all offer Class 4 lines.
What the rating does and does not promise
First, impact resistant shingles resist cracking and splitting, which is the damage that leads to leaks. However, they can still lose granules in a severe storm. Granule loss is cosmetic damage that some adjusters will not pay to repair. In other words, a Class 4 roof is far more likely to keep your house dry after a hailstorm. It is not immune to looking a bit worn afterward.
For the 1 to 1.75-inch hailstones we see most often here, a Class 4 roof typically comes through with no functional damage. Against the 4.5-inch stones that fell near Gresham, Wisconsin on July 27, no asphalt product is a guarantee.
Do Class 4 impact resistant shingles lower your insurance premium?
Often, yes, but the details vary widely by carrier and by state. Many insurers writing policies in Minnesota and Wisconsin offer a discount on the wind and hail portion of the premium for a documented Class 4 roof. The figures we have seen from customers range from modest to substantial. In addition, some carriers require a manufacturer certificate and installation date, so keep the paperwork from your roofer.
There is a second, quieter benefit. Minnesota premiums rose 34% in a single year, and the average hail claim is near $30,000. As a result, carriers are tightening terms on older roofs, including higher wind and hail deductibles and actual-cash-value settlements. A new Class 4 roof is the strongest argument you can make for better terms at renewal. Call your agent before the roof goes on, because the discount is not automatic. The Insurance Institute for Business and Home Safety maintains an independent list of tested products.
What the upgrade costs
Class 4 impact resistant shingles generally cost more per square than standard architectural shingles. The premium depends on the product line and color. Labor, in contrast, is the same. On a typical 30-square home, the difference is a fraction of a single hail deductible. The discount alone frequently covers the added cost within a few years. Our asphalt roofing page lists the lines we install.
How Class 4 impact resistant shingles compare to metal
Notably, steel panels earn the same Class 4 rating, and most standing seam systems exceed it. Moreover, metal lasts two to three times as long. The trade-off is upfront cost. That is why many homeowners choose Class 4 shingles for a routine replacement, and metal roofing for a long-term home. In either case, both earn insurance discounts with most carriers.
Our recommendation
In short, if you are replacing a roof in Minnesota or western Wisconsin, choose a Class 4 product. The hail risk here is real, the price difference is small, and the insurance landscape is only moving one way. Ask your roofer for the UL 2218 certificate and the manufacturer warranty, then send both to your agent.
Northern Lights Metal Roofing installs Class 4 shingles and standing seam metal as a GAF Master Elite® Residential Contractor. Contact us for a free inspection and a side-by-side quote: (763) 276-1390 in Minnesota, (715) 501-7663 in Wisconsin. For background on the premium increases, see our post on Minnesota homeowners insurance and hail.
