Proper drying and cleaning is important to avoid health problems associated with mold, which likes dark, damp areas. After a flood, fire, or water leak, walls and floors that were soaked for more than a few hours may have absorbed large amounts of water. These areas must be cleaned, dried, and disinfected. If necessary, remove the wall board and flooring materials to dry out these areas.
Mold has been found growing in wet insulation several months after a flood. Remove and discard wet insulation. The insulation and the wooden studs may be wet for two or more feet above the flood’s high-water level because of absorption by the materials and wicking to other areas. Organic matter from flood water must be cleaned up. Using a solution of detergent, water and trisodium phosphate, scrub all contaminated areas with a brush and rinse thoroughly. Scrub any exposed wood in the wall cavities with a detergent before disinfecting and drying.
Use fans, dehumidifiers, and air conditioners to dry a wet area. If using a dehumidifier, empty the water collection pan frequently or drain it through a hose to a floor drain. Mold can grow in the water standing in the collection pan. Air conditioners remove moisture from the air and help promote drying. If the outdoor air is dry, leave a window open to promote drying. Several weeks or months may pass before soaked walls and floors are dry enough to re-insulate and re-install wall board or flooring.
Discard wet materials that cannot be dried quickly: Carpets and carpet padding, draperies, mattresses, box springs, and upholstered furniture that have been soaked or stored in a damp environment are nearly impossible to clean and dry quickly enough to prevent mold growth. Mold thrives under wet carpet or padding and inside mattresses and upholstery. If these products have only a small amount of mold growth on the surface, they may be dried in the sun. Sunlight kills mold but it may also fade textiles, therefore sun drying may be a method of last resort in attempting to save items that are about to be discarded.
Disinfect it: Disinfectants kill mold growing on hard surfaces, such as walls and hard floors. Products that claim to be disinfectants must be registered with the Environmental Protection Agency and have an EPA registration number on the product label. Only products with the EPA registration number have been tested as disinfectants. Read labels and choose a product that disinfects and is appropriate for the material being cleaned.
During a long drying period, such as after flooding, it may be necessary to use the disinfectant every few days until the wood is no longer damp. The bleach solution kills mold only for the few minutes before the bleach evaporates. Because mold spores in the air that settle on the wet wood can germinate and develop a new colony of mold, a surface will not remain mold-free just because it has been treated once with bleach. Covering wet wood with wall board or flooring material will not stop the mold growth, as mold does not need light to grow.
After a flood, test whether wooden studs in the walls are dry enough to reseal the wall cavity by inserting a moisture probe into the wood. If the level of moisture in the wood is above 12.5 percent, continue drying the wood before resealing the wall cavities. Never mix bleach with ammonia or other household cleansers containing ammonia. When cleaning with chlorine bleach solution, wear rubber gloves and protect skin. Avoid contact of the solution with the eyes and skin and avoid prolonged breathing of vapors