Condensation is more common than you think!

Condensation is more common than you think and can become a significant problem in a property so it is important that people understand how it occurs and how to deal with it.


Condensation essentially produces moisture and therefore can also lead to a number of other defects in a property.

Source – Google

Most people will have seen damp in their homes in one form or another (such as on your window as in the photo above) however they may not realise what it is or the cause. Damp is one of the most common problems encountered in houses and can show itself in a number of ways such ‘wet patches’ on surfaces, “fluffy” mould growth and occasionally a musty smell.  If left untreated damp can lead to deterioration of internal surfaces and leave a very unsightly appearance. It can in some circumstances lead to health problems, with groups such as the elderly, young children and those with respiratory conditions such as asthma being most at risk. 

Condensation occurs naturally but can be more significant depending on how we live.All air contains a certain amount of ‘invisible’ water vapour.  As human beings we are emitting water vapour constantly. Water vapour is also emitted by the activities in the home such as washing, cooking, drying clothes, using portable heaters, etc.  Basically, there are large volumes of water vapour being emitted in your home and the amount of water vapour that is emitted is determined by the activites that we carry out and the number of people in your house at any particular time.  Condensation occurs when this water vapour comes into contact with cold surfaces and the air no longer has the capacity to hold any more water vapour.  This is also known as relative humidity which is explained below:

Relative humidity is described best as – the actual water vapour present in air to that which could be present and is routinely expressed as a percentage. The reason we refer to ‘relative’ humidity is because air has a varying ability to hold moisture vapour depending on temperature.  Warm air can hold more water vapour than cold air.  Once relative humidity reaches 100% it no longer has the ability to hold any more water vapour and it will start to condense on cooler surfaces (something referred to as ‘Dew Point’), which is the physical change into a liquid, ie. condensation.

An example of condensation would be your bathroom.  When you have a bath or shower large quantities of water vapour are produced.  Sometimes this will develop into a ‘mist’ in the room until you open the window or turn on an extractor fan.  Have you ever noticed that you get water developing on your windows and walls?  This is condensation. The same effect can be seen when cooking in your kitchen.  Have you ever wondered why this happens more readily on cold days, and in the warmer months it is hardly noticeable?  This is because the air in your bathroom or kitchen on colder days has less capacity to hold moisture than the air in your bathroom or kitchen during warmer days (warm air can hold more water vapour than cold air).  Windows are less thermally efficient than the surrounding structure such as the walls.  Therefore the internal surface temperature of the windows will be a few degrees cooler than the surface temperature of the walls.  This will mean that once dew point occurs (100% relative humidity), it will start to condense on the cooler surfaces first, i.e the windows, before it starts to condense on the surrounding walls.

Source: Google

Condensation can occur in any room in a house or within the structure of a house (interstitial condensation), including roof and floor voids, basically anywhere, where there is water vapour and cold surfaces.  If left untreated condensation can become a significant problem so it is important that people understand how it occurs and how to deal with it.  As condensation produces moisture it can also cause a number of other defects that can be found in buildings, namely timber decay such as wet rot or dry rot, as well as causing mould growth which can lead to potential health problems. 

You do not need to be a damp specialist to be able to deal with condensation or reduce the risk of it occurring.  There are numerous products on the market that claim to reduce or remove the risk of condensation in homes. These types of products may temporarily remove condensation mould that may have already occurred, or cover over damp mould. However the only certain way of reducing the risk of condensation, which will vary from building to building is to deal with the root causes.  The usual factors that result in condensation are poor thermal insulation, inadequate heating and inadequate ventilation, or any combination of these. If all of these factors can be improved then you are well on your way to reducing condensation and it’s side-effects. 




Copyright Ark Property Services Ltd 2013