Hurricanes Katrina and Rita spent only a matter of hours in the Gulf Coast region. Their aftereffects, however, will be felt for years. The region lost between 275,000 and 300,000 homes and roughly as many were damaged, according to the AIA. Figures for nonresidential buildings and infrastructure were not available at press time, but in an illustration of the extent of damage, a spokesperson for the Louisiana Department of Economic Development estimated that 5 billion board feet of lumber and 3 billion square feet of paneling would be needed for rebuilding and repairs in that state alone. Most of the repair and rebuilding in the region is likely to be completed by the end of 2008, according to research by the AIA.

Shortly after Katrina, architects, engineers, and other specialists joined local and national authorities in surveying the damage resulting from high winds, storm surges, and generalized flooding. The effects of polluted water on buildings were hard to gauge, according to experts.

In New Orleans, wind damage was greatest in buildings four stories and taller, whereas one- and two-story wood buildings bore more damage from flooding, according to engineer Stephen Kelley, a consultant with Northbrook, Illinois–based Wiss, Janney, Elstner Associates, who toured sites in Mississippi and Louisiana.

Termite damage in wood frames, along with previous flood damage, left many buildings vulnerable, Kelley noted. The flooding and storm surges undermined foundations, washed out walls, soaked and destroyed insulation, carpets, wood, and drywall. Much of the water-soaked material will need to be stripped out of buildings, although older wood, with its denser growth rings, is more resilient, and plaster can be saved in some cases. Fortunately, the region’s dry season is expected to aid the airing out, which, with bleach or other disinfectants, will allow many wooden buildings to be salvaged, according to Kelley.

Not surprisingly, buildings of lightweight, particularly newer, construction suffered heavy damage, according to Charles Harper, FAIA, of Harper Perkins Architects in Wichita Falls, Texas, who toured areas in Texas and Louisiana. In Gulfport and Biloxi, Mississippi, which saw a spate of hasty construction in the mid-1990s, many of the houses of that era were lost. Similarly, big-box and warehouse buildings along the coast did poorly. “If you’ve got big walls with no pressure release, they’re just blown out,” he said.

While many older buildings withstood the hurricanes, the cost of repairing them can be significant. In the meantime, preservationists worked to prevent the wholesale razing of buildings. “[Claims adjusters] will tend toward writing buildings off,” Kelley said. “The challenge is to not go along with that.”