How to clean up mold problems
“Small areas” of mold can be cleaned with a detergent solution. Wear a mask, safety goggles and rubber gloves. Seek professional help if there is a lot of mold or if mold comes back after cleaning. Bleach is NOT recommended, as the presence of organic (humic) materials, the pH (acidity/alkalinity) of the water, the surface material and contact time affect the effectiveness of bleach for disinfection. Since these factors are not generally controlled, bleach cannot be relied upon for disinfection. The most compelling reason for advising against bleach is that fumes are harmful but in addition, overuse of bleach will result in increased releases of chlorinated effluents which can be harmful to the environment.
“Small area” clean-up
You can clean up “small areas” of mold (fewer than three patches, each smaller than a square meter) yourself. The minimum protective wear needed are:
- safety glasses or goggles;
- a disposable dust mask (3M 8210 or equivalent); and
- household rubber gloves.
Infants and other family members with asthma, allergies or other health problems should not be in the work area or adjacent room during the cleaning.
Scrub with an unscented detergent solution; then sponge with a clean, wet rag and dry quickly. Using an unscented detergent will make it easier for you to detect residual moldy odours.
Clean the surface with a damp rag using baking soda or a bit of detergent. Do not allow the drywall to get too wet. Mold that comes back after cleaning is usually an indication that a source of moisture has not been removed. Seek professional help from a trained Indoor Air Quality (IAQ) investigator. ( Gold Seal Homes recommends Darrel Paul from Qualistat )
- Clean “moderate areas” of mold, but wear proper protective equipment and follow precautions.
- Seek professional help if there is a lot of mold or if mold comes back after cleaning.
If you follow the proper procedures and use the proper protective equipment, you can clean up “moderate areas” of mold. “Moderate” means more than 3 patches of mold, each smaller than one square meter, or one or more isolated patches larger than one square meter but smaller than 3 square meters (size of a 4 x 8 foot sheet of plywood).
- Wear a disposable dust mask (for example, 3M 8210 or equivalent), glasses or safety goggles and household rubber gloves.
- Isolate the area to be cleaned with plastic sheeting, taped to walls and ceiling.
- Infants and other family members suffering from asthma, allergies or other health problems should not be in the work area or adjacent room during the cleaning.
A small clean up should take minutes (not hours) to finish. When the clean up takes hours to a day to finish, it is suggested that you upgrade to a better filter, such as a half-face respirator with charcoal cartridges. An exhaust fan installed in a window in the room being cleaned would prevent contamination of other areas of the house as well as provide ventilation.
Vacuum surfaces with a vacuum cleaner which has a High Efficiency Particulate Air (HEPA) filter or is externally exhausted. Scrub or brush the moldy area with a mild unscented detergent solution. Rinse by sponging with a clean, wet rag. Repeat. Dry quickly. HEPA vacuum the surfaces that were cleaned as well as surrounding areas.
Cleaning wood surfaces
Vacuum loose mold from wood surfaces using a HEPA or externally exhausted vacuum. Try cleaning the surface of the wood with detergent and water. Rinse with a clean, damp rag and dry quickly. If the staining does not come off, sand and vacuum the surface of the wood with a vacuum/sander combination. It is important to vacuum at the same time to prevent mold spores from being dispersed into the air. Note that wood affected by rot may need to be replaced.
Cleaning concrete surfaces
Vacuum the concrete surfaces to be cleaned with a HEPA or externally exhausted vacuum cleaner. Clean up surfaces with detergent and water. If the surfaces are still visibly moldy, use TSP (trisodium phosphate). Dissolve one cup of TSP in two gallons of warm water. Stir for two minutes. Note: TSP must not be allowed to come in contact with skin or eyes. Saturate the moldy concrete surface with the TSP solution using a sponge or rag. Keep the surface wetted for at least 15 minutes. Rinse the concrete surface twice with clean water. Dry thoroughly, as quickly as possible.
The paper facings of gypsum wallboard (drywall) grow mold when they get wet or repeatedly wet and don’t dry quickly. Cleaning with water containing detergent not only add moisture to the paper but also can eventually damage the facing. If the mold is located only on top of the painted surface, remove it by general cleaning (see above). If the mold is underneath the paint, the moldy patch and other moldy material behind it are best cut out and the surrounding areas also cleaned. This should be done by a mold clean-up contractor. New materials may become moldy if the moisture entry has not been stopped. If this is the case, replacement of the materials should be deferred until the source of the moisture is corrected. The affected areas should be temporarily covered with plastic sheeting and sealed at the edges. Any areas that show new patches of mold should be cleaned promptly.
Article credit: CMHC