There are various actions that can be taken to flood proof structures. Electrical panel boxes, A/C condensing units, water heaters, and washers/dryers should be elevated or relocated to a location less likely to be flooded. Basement floor drains and interior and exterior backwater valves can be installed and interior floodwalls can be placed around utilities. If flooding is likely and time permits move essential items and furniture to the upper floors of your home. Keep materials like sandbags, plywood, plastic sheeting and lumber handy for emergency water-proofing. This action will help minimize the amount of damage caused by floodwaters.
The Building Division personnel are available to review and critique construction plans to assist citizens in reduction or the elimination of flood hazards.
Sealing a building to ensure that floodwaters cannot get inside it is called dry floodproofing. All areas below the flood protection level are made watertight. Walls are coated with a waterproofing compound, or plastic sheeting is placed around the walls and covered. Openings, such as doors, windows, sewer lines and vents, are closed – temporarily, with sandbags or removable closures, or permanently.
Dry floodproofing is only appropriate for buildings on slab foundations that are free of cracks. Because most building walls and floors are not strong enough to withstand the hydrostatic pressure from more than 3 feet of water, the design flood should be less than 3 feet above the slab. The technique is not recommended for houses with floors below grade, such as basements and garden apartments, because hydrostatic pressure can collapse the walls or buckle the floor.
This technique is not as desirable as a barrier, which will keep floodwaters from reaching the building. However, where there is not enough space on the lot for a barrier separate from the building, dry floodproofing may be the only alternative.
Proper maintenance of materials used in dry floodproofing is a concern. Waterproofing compounds can deteriorate over time, especially if they are exposed to sunlight. Removable closures can be misplaced. To be dependable, a dry-floodproofed building should be inspected periodically, and its owner or occupant should conduct drills to ensure that the closures can be located and put into place in time.
There are a number of local projects that combine dry floodproofing with a barrier. The building walls are made watertight and small floodwalls are built around the windows and doorways. This provides permanent protection that does not need human intervention to close the openings.