Hail Damage Roof

Asphalt shingles are designed and manufactured to withstand hail strikes up to 1.25 inches. There are different types of asphalt shingles that can withstand larger hail strikes and are graded as Class 1 (up to 1.25-inch), Class 2 (up to 1.5 inches), Class 3 (up to 1.75 inches) and Class 4 (up to 2.0 inches). While all shingles are designed to withstand at least 1.25-inch hail, performance testing shows that about 60 percent of basic 3-tab shingles failed to withstand 1.25-inch hail strikes. Large swings in temperature between winter and summer as well as repeated small hail impacts can weaken the shingles over time and make them more susceptible to damage from smaller hail. That being said, it is generally a good idea to have your home inspected for hail damage whenever a hail event produces 1 inch or greater hailstones.

Hailstorms damage roofs by allowing water to leak through the outermost layer of shingle material used. On tile, slate, and cedar roofs, hail damage is very easy to see because the cracks in the material are well defined and visible. Asphalt shingles are more difficult to see because in most cases the actual fracture occurs on the underside of the shingle. Differences in texture, color and dimensional features can make it very difficult to identify hail damage to asphalt shingles from the ground. 

Many homeowners do not spend a lot of time on their roof, and for good reason, especially if the roof is a steep slope. That said, most hail damage goes unnoticed. If you are comfortable going on the roof to check for hail damage, the best place to start looking is components made of soft metal, such as vents, flashing, etc., since these can be damaged by hail as small as ¼ inches. If your metal vents are dent free, it is unlikely that your roof would have sustained any hail damage. If you do notice hail damage on the metal components, you should begin looking for discoloration in your roofing shingles. Damaging hail will almost certainly crush or dislodge the granules on an asphalt shingle.

Once a roofing shingle is compromised by hail damage, that shingle cannot be repaired. It must be replaced. This is true with asphalt shingles, roofing tile, slate shingles, cedar shingles, etc. It may be the case that only a small number of shingles were damaged and need to be replaced. However, if enough shingles are damaged the entire roof system will need to be replaced.

When large hail strikes an asphalt shingle it causes a dimple or depression in the outermost layer. This can result in bruising or a through fracture of the shingle. In both cases, the force of a large hail stone creates so much tension that the shingle cracks on the underside. If the crack spreads all the way through the outermost layer, then it is considered a through fracture. If the hail strike cracks the underside layer and the center mat layer, but not the outermost layer that is considered a bruised shingle. A bruised shingle, when pressed with your finger, will somewhat resemble the feel of a bruised apple. Bruised shingles will eventually fail and turn into a through fracture. 

0.25-inch to 0.5-inch and larger hail can damage aluminum siding, flashing, and vents on a roof. 1-inch hail and larger can damage asphalt shingles.

Most insurance companies calculate hail damage to a roof by using test squares. A test square is a 10×10 foot section of the roof that is measured and marked off with chalk on each corner. The contractor or insurance adjuster performing the inspection then counts the number of hail strikes resulting in functional damage within the test square. While the number of hail strikes required to replace a roof may vary depending on the insurance company, 8-10 hits within a test square is a common threshold. 

While cleaning your gutters, you may notice a layer of sand or granules underneath the leaves and other debris. This may be a sign that your asphalt shingles are damaged as another feature of hail damage is granular loss. The granules are little bits of stone or ceramic material that are often dyed to achieve a desired roof color. The granules block UV light and offer additional protection to the asphalt and mat layers. Hail impacts often have granules smashed in the center surrounded by a ring of missing granules on the perimeter. The granules that were loosened from hail get washed down your roof when it rains and will often settle in your gutter. mechanical damage or normal wear and tear.