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Traditional building materials and methods have in many cases been shown to be incapable of withstanding the storm winds of 160 miles per hour (mph), or 260 kilometers per hour (km/hr), and even stronger gusts. To make matters worse, the call for repair and rebuilding has exacerbated the prehurricane shortage of cement, lumber, and steel. Moreover, the cost of building materials is on the rise as many communities in the stricken areas begin to rebuild.

These circumstances are encouraging architects to look at new materials and at new ideas about structural resistance to wind loads.

"The importance of protecting a building's exterior amazes me," says Clemson University's Scott Schiff, Ph.D., adding that builders had traditionally considered the selection of roofs, windows, and doors to be architectural detailing. "Our research at the Wind Load Test Facility found that it takes very little wind invasion to spell disaster."

21st-Century Building Materials

Structures USA, Inc. has introduced several new products created to improve building safety. One of them, GigaCrete, is a new type of concrete that can reach strengths of up to 8,000 pounds per square inch (psi), or 55 megapascal (Mpa).

Builders can use GigaCrete to make panels, floors, walls, roofs, and sheets of cement board siding and roofing. GigaCrete is fabricated with waste ash and a proprietary binder, and it is engineered to withstand hurricane-force winds. Company officials claim the material can cure in as little as eight hours.

Structures USA's Stuccomax, a super-strength stucco material that requires a single-coat application, boasts a compressive strength of 800 psi (5.5 MPa). And GigaSiding is called a sturdy alternative to vinyl or conventional cement-board siding.

Sentex Worldwide. is touting a building system that allows facilities to withstand "Category Five" hurricanes. The building blocks, which fit together like Legos, are made of a patented material called Dyligomer and a specially designed concrete called "Sencrete."

The two materials are combined in molds under pressure to create blocks that are intertwined using metal rods instead of mortar. Sentex is focusing on affordable housing projects in international markets and will soon begin building in Puerto Rico. Each house will cost about $20,000.

Shatter-Proof Window Films

Many companies already offer shatter-resistant window films designed to hold broken fragments of glass together during storms. A new twist on that theme, however, is also promising.

Hurd Millwork Company, for example, produces FeelSafe windows, which achieve an Energy Star rating for efficiency, while their storm resistance exceeds building code requirements for coastal regions. The insulated glass units are built with tempered glass on the inside and laminated glass on the outside pane to hold up in hurricane conditions.

Dr. Richard Behr, head of the Architectural Engineering Department at Penn State University is testing a similar concept called "sacrificial ply," in which two layers of glass are laminated to a thin, clear plastic sheet. During a hurricane, the exterior-facing glass ply is sacrificed to the impact of flying debris, while the inner glass ply and weather seal around the glass perimeter are preserved. Although the broken window would still need to be replaced, the inner pane protects the building's interior from the fierce winds.

Future materials are also in development. The University of Delaware's Affordable Composites from Renewable Sources program is devising techniques to manufacture soy-based plastics that can be used to build hurricane-resistant housing with woodless lumber. The U.S. Department of Energy has earmarked at least $3 million to fund the project.

West Virginia University's Constructed Facilities Center is experimenting with fiber-reinforced polymer composites to make bridges and buildings. Hota GangaRao, WVU professor of civil and environmental engineering, claims that they can tailor these materials to withstand up to 200 mph (320 km/hr) winds. "But it will be ten years before we can drive down the costs enough to commercialize the material," he notes.

Reconsidering Old Roofing Materials

With many high-tech materials still not quite cost-effective for home builders, and resourceful inventions still years away from practicality, architects can continue to incorporate some low-tech traditional materials without sacrificing the strength of their building designs.

For instance, metal roofing systems have a 120 mph (190 km/hr) wind rating and uplift resistance above that required by new building codes. Metal roofs are able to withstand wind gusts up to 157 mph (250 km/hr) — "F2" on the Fujita Scale.

"Most metal roofing materials interlock, forming a protective barrier that other roofing materials do not provide," says Bill Hippard, president of the Metal Roofing Alliance. "This interlocking makes the roof stronger," Hippard says, "and more resistant to Mother Nature's wind and hail."

The Tile Roofing Institute makes a similar claim. The organization sent technical experts to southwestern Florida to assess damage after Hurricane Charlie and reports that, despite sustained wind speeds of 145 mph (230 km/hr) and peak gusts reaching 173 mph (280 km/hr), the majority of tile roofs that were in compliance with current building codes and that had implemented improved fastening systems experienced relatively minor damage.

"With proper installation, tile roofing systems remain one of the most durable and cost-effective options in high-wind climates around the world," says Rick Olson, technical director of the Tile Roofing Institute. "The institute and its members will continue to work diligently with research organizations and local code bodies to improve performance and safety of tile roofing systems."

Indeed, research is the key to successful development of hurricane-resistant building materials. Clemson University wind engineer David Prevatt, Ph.D., says it's a question of understanding that hurricane damage is not inevitable. "If we can improve our prediction of the wind forces and failure mechanisms occurring in buildings," he says, "we can develop construction materials and building codes that will help produce safer homes and minimize the fear factor."

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Jennifer LeClaire is a freelance writer based in Miami Beach, Florida, specializing in architecture and design.

Editor's note: Addressing the problems of hurricane damage will, of course, also require the political will to ensure sturdy, affordable housing for all, to minimize population growth in ecologically sensitive coastal areas, and to give serious attention to the crisis of global climate change. In the meantime, architects must continue to seek design strategies for ever-stronger resistance to dangerous storm winds.

Hurricane Isabel caused substantial damage to residential areas of Claremont, Virginia in September 2003. Photo: Andrea Booher/FEMA On Ono Island, Forida, a federal search- and- rescue team looks for survivors following Hurricane Ivan in September 2004. Photo: Andrea Booher/FEMA Commercial building damage due to Hurricane Frances in Cocoa Beach, Florida. Photo: Andrea Booher/FEMA Glazing can be elegant and energy efficient without compromising structural resistance to storms, as demonstrated by FeelSafe windows from Hurd Millwork Company. Photo: Hurd Windows Structures USA produces full-size GigaCrete panels for floors, walls, roofs, window headers, and footer panels. Photo: Structures USA A building system from Structures USA features a high-strength roof overhang and window opening connection. Note that the header panel sits on a solid jack post slid into a butt connector. Photo: Structures USA Typical connections in a structural wall from Structures USA. Strength against hurricanes requires sturdy connections as well as sturdy materials. Image: Structures USA Stuccomax, high-strength stucco from Structures USA. Photo: Structures USA   Click on thumbnail images to view full-size pictures.