Condensation is the most common cause of dampness in buildings! It is condensation, which can lead to the appearance of mould growth. It is the presence of water condensed on the wall/ceilings and other cold surfaces which support mould growth.
Principles Involved In Condensation
The amount of water vapour that air can contain is limited and when this is reached the air is said to be saturated. The saturation point varies with temperature, the higher the temperature of the air, the greater the weight of water vapour it can contain.
Relative Humidity – The amount of water vapour in the air expressed as a percentage of the amount that would saturate it, at the same temperature.
Dew Point – This is the temperature at which water vapour changes to water droplets.
Four Causes Of Condensation
1) Too much water vapour.
2) Inadequate heating.
3) Inadequate ventilation.
4) Poor insulation leading to cold spots.
The main cause of condensation is naturally the generation of warm, moist, air by domestic activities. Moist air can come from cooking, bathing, washing, drying clothes as well as paraffin and flueless gas heaters.
The best form of heating to avoid condensation is continuous background heating. Which keeps the relative humidity below 70%.
Many houses remain unoccupied throughout the greater part of the day. Thus allowing the fabric of the building to cool down. The moisture-producing activities are then concentrated into a relatively short period.
The effect of moisture generation is further aggravated by the way houses are ventilated. Theoretically, it is possible to avoid condensation by adequate ventilation. Up to the late 1960s, there was natural ventilation in many homes, because of lack of double glazing, poorly fitted doors and windows, and open fireplaces.
Present attitudes have eliminated natural ventilation by the use of double glazing, draught excluders, fitted carpets, removal of open fireplaces and introduction of central heating – Buildings have been effectively sealed, and unfortunately provided better conditions for condensation to occur.
Ventilation is only effective if consistent throughout the whole inside of the house. Further problems are encouraged by poor ventilation.
Where stagnant air pockets are created, there is a real danger of condensation occurring where the air is left undisturbed. For example behind furniture and cupboards, often recognised by the appearance of mould growth.
Unless cold surfaces are eliminated. Condensation is inevitable (at some point). Any action must, therefore, involve lowering moisture levels in the air and eliminating cold surfaces within a building.
Areas Where Condensation Occurs;
Timber frame building, flat roofs, pitched roofs, cavity walls, subfloors, solid walls.
Four Methods To Cure The Condensation Problem
1) Reduce the amount of water vapour circulating in the building.
2) Provide adequate background heating.
3) Provide adequate ventilation to keep the RH below 70% but not to the detriment of heat.
4) Provide good insulation to avoid cold spots and conserve heat but do not eliminate ventilation.
The identification of the problem is essential by following a route map by;
Diagnosing the source – Considering the factors – Identifying the causes – Selecting the remedies – Record the details. Provided independently by a qualified surveyor ie ourselves. CALL NOW ON