Mould -
Background Information
Moulds are microscopic organisms, or fungi, found virtually everywhere, indoors and outdoors. Although they are part of the natural environment, moulds are undesirable when they grow where we don't want them, such as in homes. Over 270 species of mould have been identified as living in Canadian homes.
Moulds are always found in the air outside and inside all buildings. They come into the home in many ways - through open windows or doors, on clothing, pets, food or furniture. The problems start when mould grows inside the home. Mould has the potential to cause adverse health affects, as well as property damage.
- What are the warning signs of possible mould growth?
Discoloration is a sign of mould. However, all discoloration is not due to mould. Carpeting near baseboards, for example, can be stained by outdoor population entering the home.
Mould can be any color: black, white, red, orange, yellow, blue or violet. Dab a drop of household bleach onto a suspected spot. If the stain loses it's color or disappears, it may be mold. If there is no change, it probably isn't mould.
Sometimes moulds are hidden and cannot be seen. A musty or earthy smell often indicates the presence of moulds. But a smell may not be present for all moulds. Even if a smell is not evident, wet spots, dampness or water leaks are indications of moisture problems and mould may follow.
What causes indoor mould growth?
High moisture is the major contributor to indoor mould growth. The nutrients mould needs to thrive can be found in a number of the basic elements in a home, including dirt, dust, wood, paper, adhesives, fibers, paint, textiles, carpets, and floors. Different kinds of moulds grow on different materials. Some moulds like and extremely wet environment. Other kinds may be growing even if no water can be seen. Dampness inside the material can be enough to allow mould to grow. The actual germination of mould is caused by a number of factos, including;
Mould grows best is stagnant areas, which is why more mould is found in closets, attics and inside walls. Mould is caused largely by poor indoor air qaulity.
Organic materials such as drywall, wood, ceilings, adhesives, paper, plasters, leather, and cloth are ideal for growth. Homes with more dust and debris will most certainly produce more mould growth.
Humidity above 50% RH (relative humidity) is desirable for mould growth.
Mould thrives in areas where the moisture content is 18% or greater. Areas such as basement drywall, basement wood paneling, or cardboard boxes on the basement floor are likely targets or mould growth.
Mould growth occurs rapidly after an area is wet. The longer the materials stay wet, the higher the likelihood of mould growth.
- Water source contamination
The greater the water source, the greater the likelihood of mould growth. For example, loose toilets, pipe condensation, pipe leaks, foundation leaks, and crawl space leaks are the likely causes of mould growth.
Most moulds thrive in dark places like closets, attics, basements, inside walls, behind wallpaper, or behind refrigerators.
Temperature between 20º and 30ºC (68º - 86ºF) degrees are the optimal temperatures for mould growth.
