Do I Have Mould?

Virtually everyone has one type or another of mould somewhere in their home. Although not all types are toxic, even exposures to non-toxic mould types poses a health risk (allergies and asthma).  It is often difficult to distinguish between mould types without lab testing.

Common Mould (Non-Toxic)

The black mould that you may see growing on grouting and walls on showers and bathtubs is unlikely to be dangerous. The most common black mould is Cladosporium. Although it can be an irritant to those with asthma or respiratory disease, it is not known to pose any toxic hazard.  It can be removed with various household cleaners and bleach. The most effective way to prevent it is by providing adequate ventilation. Vent fans should be installed in all areas where dampness can occur.

Black mould growing on tiles and grout can be treated with bleach (a cup to a gallon), saturate the area for approximately fifteen minutes, then wash with a strong detergent. The area must then be thoroughly dried. Note: the bleach will kill the mould, but may not remove all the dark pigments associated with it.

Toxic Black Mould

Black Mould or what is referred to often as Toxic Mould are common terms used to describe a slimy, greenish black substance which can result in a very serious health risk. While toxic black mould is less common than other mould species it is far from rare. Cellulose is the only known host for the dangerous strains of Stachybotrys and Memnoniella, which produce mycotoxins. The mycotoxins grow in damp areas. Substances where this mould can be found include places where water has soaked wood. Ceiling tile, wall paneling, studs, cellulose insulation, drywall (gypsum board, carpet backing, cardboard and other items made of natural fibers such as cotton can act as a host. It can infest areas in the floors, walls and ceilings. Mould problems resulting from flooding should be treated professionally to avoid health risks. If the black mould is growing on materials that do not contain cellulose, it is unlikely that either Stachybotrys or Memnoniella are present. If you suspect Black Mould, have it tested before attempting to remove it.

Spores from dried mould are very dangerous and should be cleaned with caution. Never scrape or scratch dried mould, because the spores will become airborne and create a serious inhalation risk. A respiratory mask and eye protection are necessary and adequate clothing to prevent skin contact is recommended. Most mould infested areas are relatively small and are usually the result of small leaks or plumbing problems. If the problem is more internal such as on insulation or throughout a carpet, the only solution is to have the items professionally removed, before being replaced. Mouldy areas over two feet, are considered “heavily infested” and professional removal is strongly advised. Some insurance companies cover the cost of mould removal or remediation under certain circumstances. Check with your insurance agent to find out if you are covered.

According to the CDC, there are some preventative measures you can personally take to battle black mould.

• Keep the humidity level in the house below 40%
• Use an air conditioner or a dehumidifier during humid months
• Be sure the home has adequate ventilation, including exhaust fans in kitchen and bathrooms
• Add mould inhibitors to paints before application
• Clean bathrooms with mould killing products
• Do not carpet bathrooms and basements
• Remove or replace previously soaked carpets and upholstery.