Moulds can be found almost anywhere; they can grow on virtually any organic substance, as long as moisture and oxygen are present. There are moulds, fungus and dry rots that can grow on wood, paper, carpet, foods, and insulation. When excessive moisture accumulates in buildings or on building materials, mould growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. It is impossible to eliminate all mould and mould spores in the indoor environment. However, mould growth can be controlled indoors by controlling moisture indoors.
Mould and fungus reproduce by making spores that usually cannot be seen without magnification. Mould spores make their way through the indoor and outdoor air continually. When mould spores land on a damp moist spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. Moulds and fungus survive on and gradually destroy the things they grow on.
Many types of moulds exist. All moulds have the potential to cause health effects. Moulds can produce allergens that can trigger allergic reactions or even asthma attacks in people allergic to mould. Others are known to produce potent toxins and/or irritants. Potential health concerns are an important reason to prevent mould growth and to remediate/clean up any existing indoor mould growth.