After a flood, it is human nature to want to clean your home or business and rebuild it as soon as possible. Clean-up, including removing all porous materials (such as carpet, drywall, fabric and ceiling tile), cleaning all non-porous materials (such as metal and glass) and thorough drying should be done soon. There are four major steps to cleaning after the flood:
1. Remove contaminated mud: Shovel out as much mud as you can, then use a garden sprayer or hose to wash away mud from hard surfaces. Start cleaning walls at the bottom or where the damage is worst. Remember to hose out heating ducts but be sure the furnace has been disconnected first.
2. Clean: Scrub surfaces with hot water and a heavy-duty cleaner. Use a brush to scrub off all contaminants with a brush and then rinse the cleaner off.
Gail Slinde is an Extension Agent for the NDSU Extension Service in Ward County.
3. Disinfect: Bacteria can only be destroyed by disinfecting or sanitizing. You should wipe or spray all surfaces with a solution of 1/4 cup chlorine bleach per gallon of water or use a product that is labeled with an EPA registration number as a disinfectant. After wiping or spraying with the disinfectant, put the item out in the sun, if you can. This allows for additional natural disinfecting and faster drying.
4. Dry: Ventilate your home with fans, one facing into the house and one facing out in order to promote cross-ventilation. Seal the openings around the fans with cardboard, plywood or blankets so the fan can create a vacuum.
Rebuilding needs to be delayed until moisture is no longer coming through concrete in the basement and wood has dried to at least 15 percent moisture content. Wood submerged in water will absorb a large amount of water, so drying will take weeks. Meters calibrated for measuring the amount of moisture in wood allows you to be sure it is safe to rebuild your home. Meters are available at your local county Extension Service office. A $60 deposit is required to check out the meter and the deposit is refunded when the meter is returned.
Exposure to mold can cause cold-like symptoms, respiratory problems, nasal and sinus congestion, watery eyes, sore throat, coughing and skin irritations, and can trigger asthma attacks. Because some mold spores are very small they can easily be breathed into the lungs. Therefore, it is not safe to live in houses with high mold levels. People can react to molds whether the mold is living or dead.
If you can smell a musty odor or see mold, you have a mold problem. Mold grows on organic materials, such as paper, dirt, wood and soap scum. Any flooded area that was not completely dried within about one day is likely to have mold growth, so every area that is stained from water should be examined for mold growth.
There are some steps you can follow help control the growth of mold in a home that was flooded. Take any furniture, rugs, bedding and clothing outside to dry as soon as possible. Use an air conditioner or dehumidifier to remove moisture or open at least two windows to ventilate with outdoor air. Use fans to circulate air in the house.
Remove the mold, if possible. Mold can be removed from hard surfaces such as hard plastic, glass, metal and countertops. However, completely removing moisture and mold from porous surfaces such as paper, drywall and carpet padding is impossible, so these materials must be removed and discarded. When cleaning, wear a two-strap (N-95 rated or better) protective mask to prevent breathing mold spores. Remove mold from nonporous materials with a three-step process:
1. Brush or vacuum. If mold and mildew already have developed, brush off items outdoors to prevent scattering spores in the house. If items can't be moved outdoors, dampen them to minimize the number of airborne mold spores. Vacuum non-porous surfaces with a HEPA vacuum to remove loose mold and spores. HEPA vacuum cleaners filter the air and can help limit the amount of dust mites, pollen spores and other allergens in your environment
2. Scrub. Using a stiff brush, scrub with a non-ammonia soap or detergent. (Do not mix ammonia and bleach; the fumes are toxic.) Scrubbing may not completely remove mold growth on structural wood, such as wall studs, so it may need to be removed by sanding. Wear personal protective gear, including a mask and goggles, and isolate the work area from the rest of the home.
3. Disinfect. After the mold is removed, disinfect the area using a bleach and water solution or another disinfectant. The amount of bleach recommended per gallon of water varies considerably. A clean surface requires less bleach than a dirty surface. A solution of 1/4 to 1/2 cup of chlorine bleach to 1 gallon of water should be adequate for clean surfaces. The surface must remain wet for about 15 minutes to allow the solution to disinfect. Concentrations as high as 1-1/2 cups of bleach per gallon of water are recommended for wood and concrete surfaces that could not be thoroughly cleaned. Provide adequate ventilation during disinfecting and wear rubber gloves. Finally, rinse the entire area with clean water, and then rapidly dry the surfaces.
Use fans and dehumidifiers or natural ventilation that exchanges inside air with outside air.
For more flood recovery information, please call the NDSU Extension Service office in your county and check the Web site at: (www.ag.ndsu.edu/flood)