100% Protection Against Condensation
The most common form of unwanted dampness in buildings is water from the air that forms as condensation.
The air in buildings can have a high level of relative humidity due to the activity of the occupants (e.g. cooking, drying clothes, breathing etc.). When this water laden air comes into contact with cold surfaces such as windows and cold walls it can condense, causing water to be deposited. The point at which the water held in the air changes from vapour to liquid is known as the dew point.
Condensation is often associated with poor heating and ventilation in buildings, but this simple view can be misleading. Condensation is chiefly a winter problem, as the external air temperature is low and external walls and windows are cold.
Simply heating the air is unlikely to be a satisfactory solution, not only on grounds of cost, but also of practicality. Unless cold surfaces are eliminated, condensation is almost inevitable. Any remedial action, therefore, must involve both a lowering of moisture levels and the elimination of cold surfaces.
Improved heating and ventilation coupled with specific action in relation to cold spots will usually result in a significant improvement in conditions, although there may be circumstances in which alternative methods are required. A modest but constant background heat is preferable to intermittent heating since this will help to maintain a higher ambient temperature in the fabric of the building.
The installation of a small extractor fan in a kitchen or bathroom will carry away moisture-laden air from the two areas most responsible for condensation with minimal running costs. This is now required by the Building Regulations in new constructions. Extractor fans are now available which incorporate a humidistat which will control the operation of the fan within certain humidity limits. It is also possible to install fans that have an integrated heat exchanger. These have the advantage of providing effective ventilation while reducing heat loss from the property.
Where an open fire or fixed gas fire exists, a certain amount of “natural” ventilation will occur and where additional ventilation is provided it is important that this is not blocked off.
The use of specialist insulation materials fixed to the outside of the building and insulation in cavity walls will help to improve the thermal dynamics of the building and may help overcome condensation.