Severe Weather and Your Roof, Part 1: Hail
By J-Conn Roofing, Tuesday, May 6, 2014

As the seasons change, so do the weather events that can damage your roof. In April, we saw nickel-sized hail in Austin. Even larger hailstones — some the size of a softball! — fell in the northern part of Texas.

Hail occurs when we experience severe storm systems. Tiny ice pellets form in the freezing air of the higher atmosphere, usually at an altitude of 8,000 to 10,000 feet; strong updraft winds then carry that ice pellet back up into the storm system. With each up-and-down pass through the storm system, the pellet accumulates an additional layer of ice. Eventually, the pellet becomes heavy enough to overcome the force of the updraft winds; it then falls through the storm as a hailstone. Very strong storm systems have the capability to carry the pellet upward numerous times, resulting in extremely large hailstones.

The roof damage caused by hail can vary depending on the point of impact and the size of the hailstones. Most impacts can be identified as hail damage by the circular shape of the dent or ding.

  • Shingles. Damage to shingles might include pitting of shingles, loss of granules, or broken shingles. In those rare severe storms when abnormally large hail forms, it is possible (though unlikely) that a hailstone can be large enough and strike with enough force to cause damage to the decking.
  • Vents, downspouts, gutters, and flashing. These sections of your roof, made of thin metal designed only to channel water, are quite susceptible to dings and dents from hail impact. Dents will reflect the size of the hailstone that caused the damage. In the case of old metal structures that are already well into their service lifetime and already in need of replacement, a large hailstone striking in just the right spot may be able to weaken the integrity of that part.

There are several ways to check for hail damage:

  • Granules at downspouts. Check the outflow from your gutter downspouts. A pile of granules in the drainage area indicates a recent loss of granules from the surface of your shingles.
  • Safe visual inspection from the ground. Look for dents or dimples in the shingles or other roofing products on your roof.
  • Defoliation. If the trees and shrubs near your house lost a lot of leaves from the storm or even had limbs broken by hail, there is a chance that your roof may have suffered similar damage.