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Damp and Condensation

If you have damp or mould in your home the first thing to do is find the cause. Damp and mould can affect your health, so it’s important to get rid of it.

Damp and mould are caused by excess moisture. Moisture in buildings can be caused by leaking pipes, rising damp in basements or ground floors, or rain seeping in because of damage to the roof or around window frames.

In a newly built home damp can occur if the water used when the house was built is still drying out.

Download the Portsmouth City Council Damp and Mould leaflet here

Signs

The damp will form visible discoloured patches on walls and around the windows etc. This will look like clusters of black dots. This will be obvious on pale walls so be careful for it hiding behind furniture etc. Black mould can spread onto furniture, curtains and clothing so keep an eye out for this as it can damage your personal belongings. It can also create an unpleasant smell.

Damp around a window ledge

Types of damp

Condensation

This occurs when moist air comes into contact with cold surfaces like walls, windows and mirrors and gets worse in the winter. This in turn can cause black mould and damp which can damage the construction, your health and your belongings.

Rising damp

This form of damp enters from the ground and you would see damp starting at the ground and moving upwards. This occurs as a result of an issue with the damp proof course in your home construction and would need rectifying.

Penetrating damp

This occurs when moisture enters the property through external walls or the roof. It can often be caused by a building defect like a leaky pipe or some damaged brickwork.

Prevention
  • When possible dry your clothing outside; if drying them inside try dry them in front of an open window or in front of but not on a radiator.
  • Use lids when suitable for cooking as this reduces the amount of water needed and cooks food more quickly.
  • Bathrooms and kitchens are the most prone to condensation and it is ideal to have an extractor fan in these to use when bathing/cooking.
  • Around sinks, showers, bathtubs, window frames are also problem areas; take extra care to keep these areas dry wiped down.
  • Ventilate: try to open windows at either side of your house to allow for cross ventilation.
  • Keep the trickle vents on your windows open.
  • Avoid clutter around radiators as it can reduce the circulation of air.
  • Where possible keep your home warm – warm homes suffer less from condensation. Try putting your thermostat to a longer duration of a lower setting, this is more effective than short bursts of heat.
Treatment

The quicker you spot it, the easier it is to treat. If you see a small cluster of mould you can treat it, according to the instructions, with a mould and mildew remover available at most supermarket or DIY stores.

If the mould is more extreme and widespread you may need to get it professionally removed and sprayed with fungicidal paint to ensure you are not still breathing in the mould.

Once the mould is removed and providing it wasn’t caused by constructional damage then you may want to use sealants and moisture resistant paints to stop the issue reoccurring.

Mould resistant sealers may be effective for bathrooms and kitchen areas. This can be in various forms but a common one is a sealer gun, which offers precise nozzle application.

You may also consider a ‘dehumidifier’, of which there are various types available for different budget needs.

Caution: many mould removing products contain bleach so be careful with human contact or to personal belongings.

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