Closeup of condensation and black mould on interior wall

What is Condensation?

Condensation is the process of moisture being absorbed into the warm atmosphere of a property, and then (as the property cools down), the moisture condenses onto cold surfaces, such as windows, lintels, exterior walls, or windowsills.

Condensation is one of the most common forms of dampness found in buildings, and it can lead to all manner of problems. These problems might include peeling wallpapers, ruined plasterboard, rotten timber, and even lead to unhealthy living conditions and black mould growth issues.

The reason that condensation-based problems are on the rise is because of several different factors. The increased standards of insulation in the UK, double glazing, and draught proofing which makes properties more airtight have all resulted in more moisture-laden air becoming trapped within the property.

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What Causes Condensation?

The causes of condensation have everything to do with temperature, ventilation, and air pressure.

Because warm air can hold more water vapour than cold air, it follows that the warmer the air the more water it can hold, and conversely the cooler the air the less it can hold.

So, it becomes evident that if warm moisture-laden air is cooled there will become a point at which the air is so cold it will no longer be able to hold its moisture.

At this point, the excess moisture starts to revert from a vapour back into a liquid form. This is the process we know as condensation.

In practice, the effect is most commonly noticed when warmer, moisture-laden air comes into contact with a cold surface.

The warm air coming into contact with the cold surface cools the air, often to an extent where it can no longer hold the excess water, and it condenses in liquid form (condensate) onto the cold surface.

Black spot mould in bedroom

Condensation is often a seasonal problem.

Condensation usually occurs during the colder months, most commonly from October to April.

Due to windows and doors being closed, increased awareness of draught-proofing, and a rise in the use of insulation, options for ventilation in a property during the winter are either pretty limited or neglected. This lack of ventilation allows the build-up of water vapour in the house, which, in some cases, is enough on its own to cause condensation.

Our own day-to-day activity contributes quite a lot to condensation building up. Activities including boiling the kettle, drying clothes inside, taking a shower, exercising, or even breathing can all create moisture-laden air, which if unable to ventilate may well condense on cooler surfaces.

By and large, condensation is noticeable and easy to spot when it forms on non-absorbent surfaces. When it’s on windows or tiles for example it might be easy to spot and wipe clean. However, on more absorbent surfaces it may go unnoticed until mould growth or damage to decorative finishes occurs.

The musty smell associated with mould growth might start to get stronger as more condensation builds up, and ventilation or remediation isn’t carried out. It’s at this stage that you may need advice on controlling condensation within the property. For more information about the causes of condensation, you can always read through our “what causes condensation” page.

Did you know?

“An average family of four will produce 2­3 litres of water per day.”

Condensation forming on inside of window in property

How to Spot Signs Of Condensation?

How to Spot Signs Of Condensation?
The obvious places for condensation to occur is on windows, cold walls and floors, but it can also occur in roof spaces and in sub-floor areas where there is a timber suspended floor.

Where there is a suspended floor condensation may also lead to dry rot or wet rot developing in floor timbers.

The most common sign of condensation, as we all know, is water collecting on the inside of windows or on the window sill. This easily recognisable sign indicates that there is a lack of ventilation in the property and moisture laden air needs to be dispersed.

However, perhaps the most common sign of condensation is mould growth. This is usually seen as 'black spot' mould but green, yellow and white moulds may also develop depending on the conditions and the particular surface.

There are proven health hazards associated with moulds, the most common being a trigger factor for asthma. However, it appears likely that in most healthy people only heavy, persistent moulds may potentially cause a problem although some people may be particularly sensitive.

The list below shows what signs to look for when trying to stop condensation:

  • Water droplets collecting on a window or windowsill
  • Black mould may begin to grow on walls, surfaces and carpets
  • A damp musty smell
  • Peeling paint or plaster
  • Mould on clothes and fabrics

Misdiagnosis of condensation can lead to further problems at your property which is why you should contact a specialist to carry out a survey. We have added a detailed article on how spotting the differences between condensation and damp can be difficult and that there are similarities between all types of damp.

Health Problems Associated with Condensation

Condensation by itself will not cause any harm but problems arise when the issue is left untreated. If the cause of the condensation problem is not rectified condensation will start to build up and will eventually create an environment that is an ideal breeding ground for black mould growth to develop.

Black mould is a known issue that can cause problems to your health especially to those people that are vulnerable such as those that already suffer from respiratory issues (for example Asthma) or the very young.

Structural Damage and Visual Deterioration from Condensation

When moisture becomes trapped within the structure of the building this where there the real problems for the property owner begin. The long term effects of condensation can cause structural damage such as wood rot. Treating wood rot is not an easy fix and will need a qualified technician to carry out expensive remedial works.

The visual deterioration of the walls is something that no homeowner wants to see. When there is moisture trapped behind the plasterboard linings it can lead to stains occurring on the walls and water droplets on the windowsills.

If you are looking to sell a house with condensation appearing on walls, it is definitely something that would deter a potential buyer. It is something that is also a big issue for landlord owners or tenants living in the property who will constantly suffer from condensation if measures are not taken to treat the cause of the problem.

Condensation extractor fan in kitchen

What To Do About Condensation?

The longer the condensation problem is left to develop at your property the worse it will be to treat the issue. Condensation is inevitably derived from normal living activities such as washing, cooking and bathing.

Normally this moisture is vented away but in some cases, this isn't apparent, double glazing, draught exclusion, blocking of air vents and chimneys all restrict the venting of moisture laden air. This occurs especially from those areas where most water is produced such as bathrooms and kitchens.

As soon as you see the signs of condensation, you should first carry out the list of DIY tips we have listed below:

Try not to dry clothes indoors or radiators
Open windows and door where possible to improve the ventilation in and out of the property
Keep pots and pans covered during cooking to ensure the warm air is not dispersed
If you have carried out these tips and there is still a damp and condensation issue, then there is an underlying issue that needs to be resolved. To reduce the issue it is more than likely you will need professional condensation solutions to fix the root cause of the problem.

Before any condensation solutions can be carried out, it always best to seek professional advice on what the best solution is to the condensation or black mould problem. Improving the ventilation in a home is key to allowing moisture-laden air to exit the property quickly.

We provide a range of solutions including positive pressure ventilation systems that will dramatically improve the indoor air quality of the property. Our systems are designed to not just minimise condensation but eliminate condensation.

Get in Touch With a Condensation Specialist

It’s important to contact a condensation specialist who can provide specific advice for providing solutions to control and eliminate condensation along with persistent problems associated with condensation such as mould growth.

You can contact one of our condensation specialists in England, Wales or Scotland by calling 0800 288 8660 or you can request a survey online. Having a damp survey through Timberwise will be able to identify the full extent of the problem and determine whether further condensation treatments are necessary.

Request a survey

Worried about condensation? Call 0800 288 8660 or