Hail damage ranks among the most serious and challenging threats to roof system performance. Failure of a roof membrane caused by hail can result in flooding and damage to a building's inventory and equipment. This makes protecting against hail damage one of the ultimate tests of any roof system.
Although hailstorms generally are seen as a regional and seasonal problem, the Hail Belt area of the U.S. appears to be getting larger, according to research from the National Oceanic and Atmospheric Administration's (NOAA's) National Severe Storms Laboratory. Areas of the U.S. that were not particularly vulnerable to hailstorms now are receiving hail, and areas that regularly received hailstorms are seeing more storms with larger hail.
Sections of the Midwest and East are particularly prone to receiving hailstones greater than 3/4 of an inch in diameter. This size generally is considered the minimum threshold for property damage by industry professionals and government entities such as the National Severe Storms Laboratory. This makes roof protection against hail damage a greater priority. Given escalating material and construction costs, building owners and managers will face higher costs for any repairs or replacements necessitated by hail damage, not to mention the ramifications of water damage to equipment, inventory or documents.
Using information obtained during numerous site studies, I have been able to review the performances of several roof systems with regard to protection against hail damage. Although it is clear these materials perform in a more than acceptable fashion in most circumstances, they sometimes struggle to maintain their protective qualities when facing significant hail fall.