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The Condensation Season

Monday, 25th January 2010 | by: Peter Barry

Being smack bang in the middle of the condensation season I thought it would be a good time to take an overview of what can be one of the most difficult of building defects to resolve.

Condensation occurs when the air inside your property cannot hold the water vapour which is being produced and deposits it as a liquid – usually on the coldest surface.

The 3 principle factors influencing condensation are:

1. The amount of moisture available
2. Temperature levels
3. Ventilation rates

The amount of moisture available

The primary sources of moisture within a residential property are ‘life-style’ activities such as cooking, bathing, washing and drying of clothes and breathing.

In many cases a set of simple measures designed to reduce the amount of moisture produced can be enough to solve a condensation problem. I will try and produce a list of tips in a future post.

Temperature levels

At any given temperature the air can hold a given level of water as vapour – the warmer the air the greater the potential amount of water vapour that can be held. To take a simple arbitrary example – Imagine that a room of a given size can hold a maximum of 1.5 litres of water vapour at a constant temperature of 20ºC. If the temperature of that room were to drop to 10ºC the amount of moisture that could be carried by the air would be reduced to 1.0 litre. Therefore 0.5 litres of moisture would be deposited in the form of condensation.

Ventilation rates

The purpose of ventilation (as far as the control of condensation is concerned) is to replace moisture laden air from within a property with dryer air from outside. The ideal rate of ventilation is considered to be approximately 1 air change per hour. Any more than this and there is a risk that the temperature will drop and add to the condensation problem.

If you are currently have condensation problems in your property and would like some specific advice please feel free to contact us on 020 8360 7615