Condensation and Mould Growth
Every day the average household puts about 12 to 15 litres of moisture into the internal environment through normal domestic activities and just breathing!
Warm, moist air is mobile and will permeate throughout the internal space of a dwelling, resulting in condensation in contact with colder areas. This can be seen on colder surfaces through thermal (cold) bridging on corners of external walls and lintels.
In poorly heated or inadequately ventilated dwellings condensation can be serious and persistent and will invariably lead to the growth of mould. Even in warm, well ventilated houses condensation will occur in some form in the colder winter months.
Moulds can be described as simple fungi (Fungi imperfecti) and are often referred to as micro-fungi. They have the ability to adapt almost immediately to their prevailing environment and are associated with damp conditions in buildings, predominantly caused by condensation.
The moulds can cause severe disfigurement and damage to surfaces, fittings and fabrics. Prolonged exposure to mould growth can cause disintegration and disruption to some paint films. Paper and certain fibre building fabrics may also be softened and deteriorate as some mould species are capable of digesting cellulose.
There have been approximately one hundred species of micro-fungi detected in dwelling houses. The species most commonly encountered are Penicillium, Cladosporium, Mucor and Aspergillus. It is this high number of species that gives a wide range of colours in mould growth from black, green, grey, white, yellow to pink.
Moulds can produce a large number of spores into the atmosphere and this airborne contamination will vary from a few hundred spores/m3 of air to thousands of spores/m3 depending on the condition of the property.
There is invariably an unpleasant “musty” odour associated with the presence of mould and there have been health concerns with regard to the micro-fungi. In the past these concerns have tended to be confined to susceptible individuals such as the young or those suffering from asthma or with other respiratory problems.
In most cases, however it was generally considered that living in cold and damp environments was probably more detrimental to health.
Condensation and mould growth