Tips for Repairing a Flood-Damaged Building

The most important thing – give your house plenty of time to dry! Rushing to rebuild before everything dries can cause many problems. The rule of thumb is, if it takes a week for visible moisture to disappear, it will take at least another week for unseen parts to dry. Here are some inexpensive measures you can take to make your recovery easier after the next flood.


Electrical: Move the main breaker or fuse box and utility meters at least 12” above the Base Flood Elevation (BFE) for your house. (BFE is also referred to as the 100 year flood level). Label each circuit. If the electrical code allows, raise the electrical outlets and switches above the flood level.

Equipment: Relocate or elevate all equipment at least 12” above the BFE. If you plan to replace a flooded furnace, water heater, or air conditioner, install the new one on a higher floor. If your new air conditioner or heat pump will be outside, install it on a raised platform. An updraft furnace in a basement can be replaced with a downdraft furnace on an upper floor. Place heavy appliances on raised platforms. Make sure washers/dryers will not vibrate off the blocks or platform during use. A one or two foot waterproof floodwall around appliances will protect them from shallow flooding.


Wash and disinfect the studs and sills if the wallboard and insulation were removed. If rebuilding, consider metal studs and sills as they are less damaged by water than wooden ones. Pressure-treated wood resists mildew and wood-eating insects but may swell when soaked.

Warning: Some pressure-treated wood should not be used inside the house. It depends on the chemicals used to treat them. Ask your lumber company for consumer information that gives specific precautions.


If you install the wall board horizontally (four feet high), you’ll only have to replace half the wall if the next flood is less than 4 feet deep.

Leave the wall open 1 inch above the sill. The baseboards will hide the gap, but all you have to do after the next flood is remove the baseboard and the wall cavity will drain freely and air will circulate better. (Not applicable if local code requires a fire wall.)

Greenboard or other moisture-resistant wallboard may be more sturdy than regular wallboard, but replacement is still often recommended as it presents the same health hazards when soaked with floodwaters.


Particle board or plywood fall apart when wet for lengthy periods. Floor joists and some wood floors regain their shape when naturally dried. Use screws or screw nails on floors and stairs to minimize warping. Completely dry subflooring before laying new flooring or carpeting. Renail, then sand or place a new underlayment for a new floor.


Completely dry the surface before painting. This may take several weeks, but paint will peel if applied over a damp surface. Coat concrete surfaces with penetrating sealer for easier future cleanup. Coat water-stained areas with shellac or commercial stain killer first or the stains will bleed through the paint. Dryproofing requires thick plastic or rubberized sheeting. Waterproofing paints do not keep out floodwaters.

Windows and Doors

When appropriate, replace flood damaged windows with vinyl or metal framed windows. Hollow core or polystyrene foam filled metal doors are water resistant. Metal in both windows and doors may rust slightly but that is easily repaired.

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