Building shapes, roof types, and construction materials may make the difference between damage and progressive structural failure, according to Rima Taher, an expert in the design of low-rise buildings for extreme winds and hurricanes.
Many of the disaster preparation features Taher recommends for homes can also help protect commercial buildings. Square, hexagonal, or octagonal floor plans paired with roofs of multiple slopes, such as a four-sloped hip roof, hold up better under heavy wind than two-sloped gable roofs, which are common because they're inexpensive to build, says Taher, an engineer and university lecturer at the New Jersey Institute of Technology. A 30-degree roof slope offers the best results.
Connect roofs to walls with nails instead of staples and hurricane clips, she adds. This will anchor the roof more securely during extreme winds, which cause strong uplifting forces on roofs.
"This explains why roofs blow off during extreme wind events," Taher says.
Strong connections between the structure and foundation are also vital, since the failure of one structural element can trigger the collapse of another element.
In hurricane-prone areas, Taher discourages the use of tile roofs because tiles can tear off and become wind-borne debris that damages other buildings. Roof overhangs should be 20 inches or less to cut down on the building's vulnerability to uplift.