Condensation

Condensation is a common phenomenon that occurs when warm, moisture-laden air comes into contact with a cold surface, leading to the conversion of water vapour into liquid droplets. While condensation may seem harmless, it can cause a range of issues in homes, from aesthetic concerns like water stains and mould growth to more serious problems like structural damage.

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What is Condensation?

Condensation is the visible result of water vapour transforming into liquid on surfaces such as windows, walls, or ceilings. This occurs when air, which carries a certain amount of moisture, meets a colder surface, causing the air to cool down and release moisture in the form of tiny water droplets. This happens because water’s ability to carry moisture in the form of vapour is directly affected by its temperature. Warm air can carry more moisture and cold air can carry far less. The temperature at which the air will release moisture is called the dew point temperature. 

 

Causes of Condensation:

Several factors contribute to the formation of condensation in homes. Understanding these factors is crucial for effective prevention and remedy:

Temperature Differentials: The most common cause of condensation is a significant difference in temperature between the warm indoor air and cold surfaces like windows or exterior walls. This temperature contrast prompts moisture in the air to condense on these cooler surfaces.

High Humidity Levels: Elevated humidity levels within a home provide more moisture for condensation to occur. Activities such as cooking, bathing, and drying clothes indoors can contribute to increased humidity, creating conditions favourable for condensation.

Poor Ventilation: Insufficient ventilation exacerbates condensation problems by allowing moist air to linger indoors. Proper ventilation, including the use of extraction fans in kitchens and bathrooms, helps remove excess moisture from the air.

 

Enhancing air circulation is crucial for minimising condensation. Use exhaust fans in kitchens and bathrooms, open windows when possible, and ensure that your home is adequately ventilated to promote the movement of air. Historic buildings had a great deal of background ventilation by virtue of draughty doors and windows and open fireplaces.

 

Lowering indoor humidity levels is essential in preventing condensation. Consider what actions are creating moisture and whether they are ways to reduce them.

 

Lime based materials are a little considered way to reduce condensation problems in the home. Lime plaster not only allows solid walls to remain dry and warm which helps to keep them above the dew point temperature but lime plaster will also draw moisture out of the air when conditions are humid and release it when conditions are drier. Lime based materials can help to keep moisture levels in the home much more balanced.

 

Whilst insulating modern homes can reduce the likelihood of condensation it must be remembered that historic buildings were build to deal with damp and moisture differently. Moisture should be able to move freely through lime built solid walls. Whilst insulating the internal surface of a solid wall may seem like a good idea it can have the effect of preventing heat from the building penetrating into the walls. This can prevent the walls from staying as dry as they should which can have knock on effects with dampness and overall warmth of your home. Solid walled buildings function much like storage heaters, they take a long time to heat up but will hold onto their heat much longer than a modern cavity walled building that will warm up and cool down much more quickly.