Mould and Air Quality (LTB)

Residential Indoor Air Quality Guideline: Moulds

Causes of mould growth

Mould growth in a house requires the presence of nutrients, an adequate temperature, and a sufficient amount of water. The first two requirements being usually met in indoor environments, fungal growth usually results from a moisture problem (CMHC 2003). Major causes of mould growth are:

• condensation of moisture on surfaces due to excessive humidity, lack of ventilation, or low temperature;
• water leakage, e.g. from a broken pipe;
• infiltration of water from the outside, e.g. from a leaking roof or a cracked basement; and
• a flood.