By Craig Shutt
Protecting a roof against the powerful force of a hurricane presents a difficult challenge, especially in retrofit applications. But recent hurricane damage has indicated that the protection is worth the time and effort — and the extra money.
"Looking at areas hit by hurricanes, it's apparent that newer homes definitely hold up better than older ones, because they have roofing systems designed to help protect them in hurricanes," says David Tyson, president of David Tyson & Associates in Charlotte, N.C.
The key to protection comes in following the recently enacted International Building Code, which sets various wind zones and specifications that must be followed in each one. In the highest zone, designs are created to withstand 165-mph wind gusts. The code specifies hardware, the number and types of nails required and even specific nailing patterns. "Inspectors are inspecting these systems specifically; the programs are being enforced," David says.
Protection starts with bolting down everything and connecting each level to the next one, David explains. That means creating concrete footings with threaded rods that connect to the floor system. Hardware then connects the floor system to the walls, which bolt to the second floor. The top walls are then bolted to the roof line, using hardware that nails into the rafters.
Additional support can be provided by truss bracing, according to Against the Wind, a pamphlet produced by the Red Cross and the Federal Emergency Management Association. The bracing consists of 2x4s nailed lengthwise along the home's gables, overlapping the ends across two trusses. The braces are installed 18 inches from the ridge, in the center span, and at the base, leaving 8 to 10 feet between the braces. End bracing also can be installed by placing 2 x 4s in an X-pattern from the top center of the gable to the bottom center of the fourth truss and in the reverse pattern.
Protecting older homes
Retrofitting existing homes to provide this protection can be difficult, David says, although a variety of types of hurricane straps are available to help protect any type of roof design. In some cases, homeowners can use an exterior strap that literally straps over the top of the house and connects to the foundation on each side.
Typically, however, the roof connections and bracing can be accomplished from inside the attic, making those elements easier to perform. And David suggests that any time new siding is put on the home, hurricane straps and other hardware can be added first before the new exterior appearance is added.
Protecting shingles during a hurricane or other strong storm can be difficult. David stresses the importance of following the manufacturer's guidelines and ensuring that the recommendations for nail depth and number of nails are used. "Some contractors try to speed up the job by using three nails, but many require five," he says.
It's also important to ensure that shingles with self-sealing tabs actually self seal. In some cases, they are shipped with a protective film that must be taken off. In addition, the tabs are designed to melt under the hot sun, but if the sun isn't hot for awhile, they may not fully adhere as designed.
Interlocking, heavy-gauge shingles can provide the best protection, but these begin to cost significantly more money, David notes. "Shingle selection often is based on the neighborhood and the pocketbook, and you can end up paying a lot for higher-end shingles," he says. "But this is one area where you get what you pay for."
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