Locate the affected area by simply following your nose. Even when the growths are not apparent, the musty smell is a sure giveaway. An in-depth visual inspection will eventually reveal telltale black, gray or white and often fuzzy patches.
Investigate hidden areas for additional mold growth. Mold spores move along air currents and in water; a growth on a basement wall is a good reason to check air ducts, exposed wood trim, and the underside of any carpeting.
Determine the extent of the problem. This will help you make the crucial decision between dealing with the problem yourself and calling in a pro. The U.S. Environmental Protection Agency recommends seeking professional help when mold affects an area larger than 10 square feet. You may also need help if mold or mildew and moisture have saturated porous materials such as carpets, wood sills, or drywall.
Dress appropriately for a dirty job. Wear a long-sleeve shirt and long pants, disposable booties over footwear, and a dust mask designated “P100” or “N95.” Also wear long rubber gloves.
Vacuum the affected surfaces and surrounding area using a vacuum equipped with a high efficiency particulate air (HEPA) filter.
Clean obvious patches of mold or mildew by wiping surfaces with a clean cloth moistened with a diluted bleach solution of 1 cup bleach to 1 gallon of hot water. If the patches are stubborn, use a stiff scrub brush. Rinse and repeat as necessary to completely remove any traces of the mold or mildew.
Remove compromised materials such as damaged wood trim, drywall, or carpet. Carefully cover the material with plastic sheeting and remove it. Contain these materials in plastic trash bags, cutting them up as necessary to make them fit. Dispose of the bags according to local sanitation guidelines.
Vacuum the basement once you’ve finished removing the affected materials. Clean hard-to-reach areas such as pipes using a clean cloth moistened with the dilute bleach solution. The goal is to clean the basement top to bottom, to remove any dust that might contain spores.
Remove and wash your clothing when finished, and dispose of the mask, booties, and gloves. Carefully roll up the plastic drop cloth and dispose of it in a plastic trash bag.
Remedy the conditions that led to the mold in the first place. This may involve installing a high-volume dehumidifier, adding a sump pump, ensuring proper drainage away from the exterior walls of the basement, or repairing cracks or holes in the walls.