by Todd Hewitt – president Texas Fifth Wall Roofing
Whether its hurricane season or hail and tornadoes, Central Texas is a focal point for natural disasters. Severe weather events seem to occur more and more frequently. Rough weather is hard on roofs and can result in major disruption and inconvenience if the roof design is not up to the challenge and you are caught with preventable roof leaks.
Texas Fifth Wall Roofing Systems has recognized a recent pattern of recorded windspeeds exceeding roof warranty limits. According to an analysis conducted by Sperling’s Best Places, a publisher of city rankings, of the top 8 highest tornado risk areas in the U.S., five are in Texas.
The limits are determined based upon the wind resistance of the particular roof design specified. One of the most effective strategies to avoid unwarranted leaks is to specify a design that qualifies for a high wind speed warranty. While the typical limit is 55 mph, many manufacturers offer limits of 72, 80 or even 120 mph. We have observed speeds up to 79 mph near our client’s properties so 80 to 90 mph warranties seem worth consideration. Testing laboratories like FM Approvals may list ratings such as 1-60, 1-90 or 1-120. You would think that these ratings refer to miles per hour, but they refer to uplift pressures in pounds per square inch. Furthermore, the roofing designer or specifier sometimes assumes if there is a design wind speed requirement of 90 mph, then the roof system must have a 1-90 rating, which is not always true — there are a number of factors to be considered, including:
- The building’s overall height.
- The terrain surrounding the structure.
- The type of roof deck on the building.
- Whether or not the existing deck meets Factory Mutual minimum standards.
- Whether or not the building is a “special use” facility such as an airplane hangar, a hospital or a facility with many large dock doors, etc.
- Whether or not the building has parapet walls, and if it does, their height.
The large available increase in warranty wind speed limits is a great value considering the modest additional cost. The typical roof has a 17 year service life and enhanced designs should last at least 20 years. Thus, if you are considering a roof replacement, it is a good idea to take wind conditions into consideration now.