When Mould becomes a Problem

Moulds will grow and multiply whenever conditions are right— when sufficient moisture is available and food is present.

Be on the lookout in your home for common sources of indoor moisture that may lead to mould problems:

  • Flooding
  • Leaky roofs
  • Sprinkler spray hitting the house
  • Plumbing leaks
  • Overflow from sinks or sewers
  • Damp underfloor space
  • Steam from shower or cooking
  • Humidifiers
  • Wet clothes drying indoors or clothes dryers exhausting indoors
  • Unflued gas heaters
  • Warping floors and stains on walls and ceilings can be indications of moisture ingress
  • Condensation on windows or walls is also an important indication, but it can sometimes be caused by an indoor combustion problem!
  • Fuel-burning appliances even if routinely inspected by a licensed gas fitter.


Yes, if indoor mould contamination is extensive, it can cause very high and persistent airborne spore and mould fragment exposures. Persons exposed in this way can become sensitized and develop allergies to the mould or other serious health problems.

Mould can damage your building in severe cases as well as your furnishings, such as carpets, sofas and cabinets. Clothes and shoes in damp closets can become soiled. In time, unchecked mould growth can cause serious damage to the structural elements in your home.