What are Wind Ratings (Resistance and Shingles)?More roofing definitions
Homeowners contemplating the installation of a replacement roof may be concerned about the wind resistance of construction materials used on their homes -- especially in areas with a high concentration of tornadoes or hurricanes. Underwriters Laboratories (UL), the international testing organization, is responsible for the determining such products' endurance and began investigating roofing products in 1903.
UL's test method (ANS/UL 2390) has found the wind resistance of asphalt shingles with sealed tabs to be between 60 to 150 mph. Consumers can check individual UL listings - usually present on the product packaging - to find out the wind velocity resistance of individual brands. This type of roofing material is classified based on wind speed resistance and with wind ratings categorized as follows:
- Class A (for winds up to 60 mph)
- Class D (90 mph)
- Class F (110 mph)
- Class G (120 mph)
- and Class H (150 mph)
Homeowners should be aware that wind velocity varies across a roof and causes different uplift pressures depending on wind gusts, the landscape surrounding the home, the shape of the roof, and the design of the roof edge. A professional roofing contractor or architect can advise consumers on the best choice of roofing material for specific situations.
International building and safety codes provide specific installation requirements for wind and uplift resistance to help ensure standards are adhered to and to minimize damage to homes from high winds, tornadoes and hurricanes. Proper installation methods along with following existing building codes can go a long way in protecting homeowners from wind damage to their roofs.