Landlord’s guide to condensation control & mould

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One of the biggest problems for landlords is condensation and mould. If it isn’t dealt with swiftly it can lead to the growth of black mould on decorated surfaces, clothes, shoes and other soft furnishings. This isn’t simply an issue of unsightly mould but also a potential health hazard, especially those who have respiratory health concerns.

Unfortunately it can also lead to landlord/tenant disputes even though landlords aren’t in control of the day to day conditions within their rental property. This is why it’s vital that both landlords and tenants know how to prevent condensation build up.

What is condensation?

Condensation occurs when water vapour generated throughout the day is no longer held in the air by the heating and forms as water on windows, walls and cold surfaces.

Water vapour can build up throughout the day in various ways. In a household of just two tenants, up to 15 pints of water are held in the air from the following activities:

Causes of condensation and damp, e.g. ironing, cooking, showering etc.
In a house of five or six people, carrying out normal daily activities can easily generate 25-30 pints of water. Even breathing adds moisture into the air!

Preventing mould

Mould spores, which are in our environment all the time, develop and proliferate when their food source – condensation – forms on a regular basis in significant volumes. So how do you stop this much water vapour being generated or ending up as condensation?

Often, the advice given is to turn up the heating and keep it on for longer but who can afford to keep heating on for longer periods?

The best solution is to control the internal levels of humidity. Humidity is the measurement of water vapour held in the air. If humidity exceeds 70% on a consistent basis, condensation will form, leading to black mould growth.

Properties should be maintained at a humidity level of between 40-60%.

Controlling humidity

Controlling internal humidity is a balance of measures. First and foremost, where possible, ventilate the property by opening windows from front to back, side to side, on all floors. What you are trying to achieve is a change of internal air quality on a regular basis.

However, be aware that this isn’t always the best thing to do in the winter, as letting in cold air will lose a lot of heat.

These tips will help you keep humidity levels steady in your rental property: