How to Design a Wind-Resistant Single-Ply Roof System (2 of 4)

More for tips from Stan Graveline, VP of technical services at Sika Sarnafil to come.

Know the difference between wind speed and wind pressure. Wind speeds need to be converted to pressures by applying the appropriate coefficients to account for a building's surrounding ground roughness and topography, and the roof's height, shape, and slope.

“People don't understand the difference between wind speed and pressure, so they just specify FM 1-90 as the de facto standard, which means 90 pounds per square foot of uplift resistance,” Graveline says. “This results in roofs that are vastly over-designed for all but hurricane-prone areas, thereby costing the owner many thousands of dollars more without any additional benefit.”

Instead, Graveline says Building Teams should design to comply with the relevant requirements of the building codes. In this case, roof wind uplift designs should be calculated according to the American Society of Civil Engineers Standard 7: Minimum Design Loads for Buildings and Other Structures.

High Wind Projects