Are Old Houses More Prone to Condensation

Are Old Houses More Prone to Condensation

By Ruth MacEachern

Product Manager

Condensation is caused by moisture being released by the air onto cool surfaces and is often seen as droplets or streams of water on bedroom windows in the morning.

The amount of moisture that can be carried by a given volume of air is dependent on the temperature of the air. Warmer air can hold a higher water content than cooler air. As air cools, it can no longer hold as much water vapour, and this is released as condensation.

Without good ventilation to keep air circulating and to remove the humid air, all houses can be susceptible to condensation and the problems that it leads to such as damp and mould, but the problems are often more pronounced in older properties.

Why are old houses more prone to condensation

Modern housing is typically built to be airtight and energy efficient. This means that the insulation properties of the building are intended to retain as much heat as possible. Dual skinned walls with cavity insulation, and thick insulation in the loft stop heat loss through walls and ceilings, and this means that internal surfaces temperatures do not fall as quickly. Double glazed windows also help to reduce the temperature gradient in the property. A house filled with warmer air will typically see less condensation simply because the dew point of the air where the water vapour becomes liquid is not reached as frequently.

In older properties, weaker insulation will mean that walls, ceilings, and windows are typically cooler to the touch, and the overall air temperature can fall more quickly once heating is turned off, and this means that there is more likelihood of the dew point being reached.

What about Ventilation

As noted above, modern homes are typically designed to be more airtight than their predecessors. While this helps to keep temperatures higher, it does mean that there is less opportunity for moist air to escape without the use of extractor fans in key rooms such as bathrooms and kitchens. As a result, modern houses can also be prone to condensation simply due to more moisture being trapped.

Are the consequences of condensation more serious in older properties?

In older properties without good ventilation or insulation, condensation is more likely to become a major problem. One of the key areas where this is the case is around windows. While modern homes typically have UPVC window frames, wood is more commonly used on older houses. Moisture from condensation can soak into the wood causing damp levels to build up, and ultimately the wooden frames will start to rot. Many landlords choose to upgrade their windows to modern double glazed plastic frames to avoid this.

Another area where older properties can suffer more as a result of condensation is the build up of damp in walls. When moisture from condensation soaks through paint and gets into the plaster, it can quickly develop into damp patches that will, in time, cause the plaster to crumble and lead to the growth of mould which can be expensive to clean up and repair.

What can you do

The most effective way of reducing the amount of condensation in a property is to improve the ventilation in the rooms where it is generated. High quality, efficient extractor fans in bathrooms and kitchens remove moisture at its source and stop it escaping into the rest of the property. Many landlords opt for extractor fans with moisture sensors which start and stop automatically to keep humidity at a safe level.

As a landlord, protecting your investment property is important, but it needs to be done in conjunction with tenants. Ensuring that they are aware of simple rules to prevent condensation such as avoiding drying clothes on radiators and keeping bathroom and kitchen doors closed when in use is a straightforward way to minimise condensation. It is also important for tenants to let a landlord know if they have started to see problems with damp and mould in the property as early as possible to reduce the cost of repairs.

Find out More

If you are concerned about the risk to your property from excessive condensation, please contact EnviroVent today. Our local ventilation specialists can visit your properties to identify the sources of condensation and provide help and advice about the best way to get rid of it for good.

Simply enter your postcode below to find a local specialist and book your home survey today.