Condensation

Condensation is the most common form of damp in buildings and accounts for the majority of damp problems reported, however, because condensation occurs at low levels starting in a corner and spreading along the length of the wall, it is often misdiagnosed as rising damp.

What is Condensation?

Condensation is caused by water vapour in buildings. It occurs when a property has poor ventilation and high levels of humid air become trapped with in it. When this humid moisture comes into contact with cold surfaces such as windows or external walls it condenses; meaning the lower air temperature turns water vapour into water droplets. This is known as the dew point. On impervious surfaces i.e. glass, beads of water collect, however on permeable surfaces such as wallpaper and porous plaster moisture is absorbed into the material meaning that the problem of condensation is not always initially obvious.

Signs of Condensation

Condensation is directly associated with mould growth and it is this the occupier often notices first and gives a sign of the scale of the condensation problem. Condensation is a seasonal issue and it becomes more apparent in the winter months when the ventilation of properties is usually low, allowing a build up of water vapor in the house.

Condensation can occur in windows, cold walls and floors, however, less obviously, it can also appear in more concealed area such as roof voids and suspended floors, which leads to the risk of rotting timbers.

It is also important to note that condensation can occur well away from the site of water vapor production and can cool and condense on cold walls throughout the property.

Here are a list of the main signs of condensation to look out for in your home:

• Damp walls
• Blistering paint
• Water droplets on windows and paint
• Peeling wallpaper
• A musty smell
• Black mould growth
• Health problems

Reducing Condensation

There are some steps that can be taken to reduce condensation within your home.

• Avoid drying clothes on radiators and in front of fires
• Use an extractor fan when cooking(not just a recirculating type)
• Install mechanical extract fans in bathrooms and kitchen (if fitted).
• Ensure there are no rapid temperature changes by having a constant low level of heating in each room if possible.
• Do not use portable gas heaters as these produce water as a by product.
• Improve insulation to cold areas, ie, thermally insulate cold bay window walls.
• Always place lids on pans when cooking.
• Open windows and doors when possible.

Ventilation

The building regulations state that every dwelling should have a means of ventilation.

Many homes we visit have no or very basic ventilation, together with bricked up unused chimney flues and sealed windows with edge to edge flooring our homes have become sealed up or less vapour permeable.