Winter mould problems and how to prevent them

Mould in rental properties is an expensive and time-consuming problem faced by local authorities and private landlords

As the winter period arrives, tenants close windows and doors and turn up the heating, this prevents airflow in your properties and their homes. This is similar to wrapping the property in a plastic bag. When there is no ventilation and plenty of moisture, which is created through ordinary activities such as showering, drying clothes, cooking and even breathing, mould spores will multiply and then colonise areas giving a fungal attack in the property. It is interesting to note that typical moisture emission rates in a four person household can be between 5 and 10 litres of water in a 24 hour period. This level can increase by 10 to 20 litres if washing and drying laundry takes place.

Most fungi grow at moderate temperatures in the range of 10-40 oC. These mould, blackspot and fungal spores will feed off surfaces in dwellings where nutrients can be found, such as paper, paste, paint, bath or shower areas (silicon sealers, etc) and general surface contaminants which are present in even the cleanest of dwellings.

Mould prevention

Apart from the general appearance of mould which can cause physiological problems other health risks exist. Rhinitis, asthma, alveolitis and other bacterial infections may be aggravated or instigated by the presence of mould.

Mould and blackspot are now becoming a real health and safety issue for local authorities and increase dramatically during the winter period.

Installing ventilation systems in order to reduce the amount of moisture in a property can assist in reducing these growths but may not completely eradicate the problem.

Ideal air change rates (ACH) should be maintained at around at least 4 per hour, but should increase considerably in areas of high damp and humidity i.e. laundry areas and bathrooms. In these areas of high moisture output, washing and drying rooms, a mechanical extraction ventilation system should be employed.

Modern dwellings with cavities are less prone to mould growth due to increased insulation. Thermal insulation should be considered on older, single skin, properties to reduce the effects of condensation.

Where a dwelling is suffering from water penetration or rising damp, these must be rectified at source, as must any general leaks.

Established mould growth can also be killed by fungicidal treatment, but this will be short lived unless precautions, such as those listed above are taken.