Everybody is confronted by mould on indoor surfaces at some stage. Mould makes its presence known by a musty, earthy odour and unsightly white, green, dark grey, dark green, black or brown spots and stains. It is often found in showers, bathrooms and in the kitchen.
Quite often all that is needed to get rid of it is a good clean with household products, but the problem is more serious when mould growth occurs in the built structure itself. When mould grows on (and into) plasterboard and other building materials, it may result in damage severe enough to warrant the replacement thereof. Such repairs can be very costly.
An uncontrolled mould problem can have other financial consequences such as the loss of tenants in an investment property and a decrease in the value of a property.
A mould problem in a building may also impact the health of inhabitants with allergies, asthma, weakened immune systems and/or other health conditions. According to a 2018 Parliamentary report the prevalence of a condition referred to as Chronic Inflammatory Response Syndrome (CIRS) has been described in Australia and internationally as a biotoxin related illness.
Where does it come from?
Mould and mildew are living organisms known as fungi. They are present virtually everywhere, indoors and outdoors.
It is estimated that there are over a million species of mould, and indoor air will normally contain thousands of mould spores in each cubic metre.
It is only when conditions turn favourable that mould growth tends to get out of hand and cause a problem. Mould can then take hold and spread very quickly – from 24 hours to 10 days after the provision of growing conditions.
When the conditions are right, mould can grow on any surface – even glass and stainless steel.
Mould on building materials
When mould is spotted on internal surfaces such as (painted) plasterboard walls and ceilings in a bathroom, it is most often the result of poor ventilation and condensation, but other conditions can also turn a building into mould heaven.
Excessive mould growth is always a risk after flooding in a building, and at other times a hidden leak may go unnoticed and cause severe damage. Other risk factors are poor building design or the choice of the wrong building materials for unique situations, such as indoor swimming pools or saunas.
Mould growth can also occur during the construction of the building, for instance on the internal barriers of party wall systems of adjoining townhouses before the structure is roofed over.
To find out more about mould and how to avoid, assess and treat mould growth on indoor building materials such as plasterboard, download our latest whitepaper, The Knauf Guide to Indoor Mould.