Indoor mould rarely presents a safety hazard to a home's inhabitants, with the important exception of Stachybotrys chartarum, known colloquially as "toxic mould" or "black mould." The typical homeowner may find it difficult in trying to identify a mould species as either toxic or benign, so in the interest of safety, it is always best to simply remove any mould that you find growing indoors.
Mold and Moisture
Microscopic mould spores exist practically everywhere, indoors and out, but spores will not form a mould colony unless they land on a moist area. Therefore, the primary cause of mould growth indoors is the introduction of extra moisture, for instance, from a malfunctioning or leaking appliance. If mould consistently occurs in one part of the home, the chances are good that there is excess moisture in that location. Frequent mould outbreaks on walls and ceilings, for example, may suggest a leaky ceiling or defective air conditioning components.
Removal From Walls and Ceilings
Regardless of where mould is growing, it can be removed in a few simple and painless steps. First, scrape or scrub off any physical mould patches and throw away the scouring pads and paper towelling immediately. Discard the trash bag you use to throw away the growth and cleaning implements to prevent dislodged mould spores from landing and forming new mould colonies. The area over which the mould was growing can be cleaned and disinfected with a homemade bleach solution of 1 cup bleach to 1 gallon water, or with a commercial disinfectant. Make sure that the entire area you clean dries completely. Use a fan if the conditions are exceptionally humid.
The second, and arguably more important, component of cleaning mould growth is to eliminate the source of extra moisture that caused the mould to grow there in the first place. Indeed, to clean up the mould without eliminating the extra moisture is simply to create the conditions for future mould growth. If you are unable to determine what is introducing extra moisture to your walls and ceilings, have a home inspection professional examine the area for you.
Stachybotrys Chartarum Toxicity
For anyone facing a problem with indoor mould growth, it is important to know the signs of mould toxicity. Exposure to any moulds by those prone to mould allergies or with diminished immune system function will cause minor irritation. Prolonged exposure to toxic Stachybotrys chartarum moulds can cause coughing and other respiratory symptoms in healthy people and can cause breathing problems in asthmatics. If anyone in your home is experiencing these symptoms after mould is found indoors, seek medical attention right away.