Condensation

This is the most common form of dampness in the UK. Our houses become more and more ‘sealed’ with better insulation and double glazing. Fire places are blocked, draughty windows and doors are replaced, leaving moisture no way to escape. On the other hand we produce more moisture by doing more laundry and having more baths and showers. An average person produces about 4-5 litres of moisture par day. This leads to more and more condensation problems, mainly in the winter months.

The principle of condensation is quite simple. At any temperature air can hold a certain amount of water vapour. The warmer the air, the more vapour can be held. Should warm, moisture filled air cool down at some stage it will reach a temperature where the air cannot contain the moisture anymore. The air will start releasing the water vapour which we call condensation. This usually happens on cold surfaces because this is where the air is cooled. Should the surface be non porous (like glass windows or tiles) it can form droplets. When surfaces are porous (like brickwork and plaster) it usually cannot be seen because it is absorbed by the plaster and brickwork.

When condensation occurs over a longer period of time, bricks and plaster will get damp and mould can start to appear. This will happen around windows, in outside corners, bay windows, in colder bedrooms and often in or behind wardrobes built onto an outside wall. The mould is usually black but can come in all kinds of colours (green, yellow, off white).

Condensation over a longer period of time can affect plaster, wallpaper, paint, fabrics (clothes in wardrobes), but also window frames and other woodwork since it can cause wet and dry rot can develop. An unmistakable musty smell is often associated with condensation.

Houses with condensation problems are usually unhealthy houses to live in because fungi and bacteria and thrive in warm, humid air.

 
The Cure

Spores of mould are in the air everywhere and little can be done about that, however we can prevent them from growing by reducing humidity levels indoors.

Increasing ventilation and heating, cutting down on production of moisture indoors should lead to improvement. But sometimes it is difficult to open windows because of noise or security reasons. Also there are cases where the above measures are simply not enough because the causes of condensation lay in the structure of the building (often to be seen in bungalows and ground floor flats). In houses where there is rising or penetrating damp there is often increased condensation due moisture evaporating from the damp walls.

In these cases the Positive Pressure Ventilation Sysytem can be the solution because it builds up a pressure within the house using fresh clean air. The build up of pressure then pushes out the stale air. In addition to the fitting of our system our surveyors will talk you through additional measures you can take to end up with a dry healthy house.

Warning

Condensation problems are often misdiagnosed as rising damp by representatives of damp proofing firms resulting in people paying out for a chemical damp proof course which will have no effect at all. Damp readings in outside walls at a low level do not have to be rising damp. As a rule of the thumb, there is an element of condensation involved when there is black mould growth since rising damp usually brings salts and minerals along from the ground which makes the surface not suitable for mould growth. Many damp proofing firms however only offer chemical or electrical damp proof courses which are aimed at rising damp only.