Baltimore, MD -- Flooding causes more than 90 percent of disaster-related property damage in the United States each year and accounts for more than 75 percent of all Presidential disaster declarations. Although Hurricane Isabel was responsible for destroying and disrupting many Marylanders' lives last month, local and federal guidelines can help reduce the damage to your home should another flood disaster strike.
"Over the last decade, property damage related to flooding has averaged well over $3.5 billion a year," said Bill Lokey, federal coordinating officer for the U.S. Department of Homeland Security's Federal Emergency Management Agency. "Because of these astronomical figures, federal, state and local floodplain management programs are continually being developed to design and improve technology that will help lower individual and community losses from flood disasters and lessen money spent in recovery efforts from repeated disasters in the same areas."
Many Maryland communities have used these guidelines to make building codes that reduce the risk of damage from flooding. New houses and, under certain conditions, renovated houses must meet these codes. Older houses can obtain the same level of protection if they are modified to meet the new codes.
The new building codes generally just apply to construction in a floodplain. Your bank, mortgage lender, or insurer can tell you if your home is in a floodplain. Homeowners can meet the floodplain building code by elevating their lowest floor (including basement) to a safe level, known as the "Flood Protection Level" or FPL.
The FPL is determined by adding a margin of safety to the base flood elevation (BFE). The BFE is the height that you can reasonably expect a severe flood to reach. Local officials determine the margin of safety above the BFE, called "freeboard." In Baltimore County, the freeboard is one foot.
When a house is properly elevated, the living area will be above all but the most severe projected flood. Elevated homes have a foundation, but do not have a conventional basement. The foundation may be closed, if proper venting rules are followed, and may be used to garage vehicles and for storage. Everything stored in the foundation area is considered expendable. All utilities must be raised above the FPL. This usually entails raising the main electrical panel, the home heating and air conditioning system, and the washer and dryer.
In the areas hardest hit by Hurricane Isabel, the houses in Baltimore County that conformed to current floodplain building codes were not damaged.
During the process of elevating a home, most wood frame, masonry veneer, and masonry houses are separated from their foundations, raised on hydraulic jacks, and held by temporary supports while a new or extended foundation is constructed below. The living area is raised and only the foundation remains exposed to flooding. This technique works well for houses originally built on basement, crawlspace, and open foundations. When houses are lifted with this technique, the new or extended foundation can consist of continuous walls or separate piers, posts, columns, or pilings.
Local governments establish guidelines for building code regulations specific to its community's needs. Before building, individuals should check with appropriate building permit and zoning boards in their city or county.
Although different specifications are adopted depending where you live, most guidelines can be expected to reflect requirements similar to Baltimore County's, which are listed below:
- The lowest habitable floor must be at or above flood protection