Hail Damage to Clay Tile Roofs

Significance

• Intact clay tiles keep water out of the roof and provide an insulated layer to keep homes cool in summer and warm in winter. When these tiles are cracked or broken by hail, they allow air and water to pass into the roof. This may increase heating and cooling costs. It also encourages rot in the roof sheathing and supports below the tile. Even tiles only slightly damaged by hail need immediate attention, since they break more easily in subsequent storms. Failure to address tiles broken by hail could lead to the need to replace the entire roof, a costly, labor-intensive process.

Damage

• When hailstones strike clay tiles, they produce irregular fractures that emanate out from the point of impact. According to "Hail Damage to Clay Tile Roofing" by Timothy P. Marshall, et al., hailstones smaller than 1 1/4 inches in diameter usually do not damage clay tiles. However, 1 1/2-inch ice balls broke corners and edges on all tiles they struck. The center of the tile generally is stronger and more crack-resistant than the edges, which easily break. Hailstones do not cause pitting or spalling, problems that tend to result from repeated freezing and thawing.

Repair

• Hailstones usually seriously damage tiles, requiring tile replacement. Smaller stones or large hailstones traveling at slower speeds may only chip or crack the tile. Repair these tiles using a roof-tile adhesive or sealant meant for use on clay. This type of adhesive allows homeowners to make minor repairs without needing to fully replace the tile.

Replacement

• Replace broken clay tiles by using a hacksaw blade, slate ripper or pry bar to remove the nails or pegs holding the tile in place. Use a piece of scrap wood under overlapping tiles to allow better access to the fasteners. In some cases, the damaged tile may need to be broken with a hammer for successful removal. When possible, re-nail the new tile through the nail holes for the previous one. When these nail holes aren't easy to reach, use a tile clip or a piece of copper sheet nailed to the support to hold the tile in place. Take care to avoid damaging nearby roofing, especially on roofs made of high-profile tiles, such as the barrel type, which are fragile and easily shatter.