Managing mould

During the colder months, mould can be a major problem in many homes - but do you really know what this is, or how to remedy it?

What is condensation?

The likelihood is that it is condensation rather than damp. Condensation it is caused when warm, moist air hits a cold surface such as a window or external wall. This then condenses, running down the surface as water droplets. If left, this can develop into black mould which not only looks and smells bad, but can cause damage to the property and your belongings – and it can cause health problems too.

Where does condensation happen?

Condensation can be a problem in any home no matter its age and is often worse in properties that have been modernised, as ventilation and the circulation of fresh air is reduced. Areas most prone to condensation are:

Cold surfaces such as mirrors, windows and frames
Kitchens and bathrooms where a lot of steam is created
External walls, walls in unheated rooms and cold corners of rooms
Wardrobes/cupboards where cold air can be trapped
Behind other furniture against an external wall due to lack of ventilations

Condensation or damp

There are of course other mould related problems such as rising damp or penetrating damp, but this is much less common than condensation.

Rising damp: This is moisture pulled from the ground upward through the floors and walls, and can happen where there has been a failed (or inadequate) damp proof course previously. Rising damp can be easily identified by a tidal like mark along the wall where the moisture stops, which can reach a height of 1 metre.

Penetrating damp: This is any water that has found its way inside a property from the outside and is usually moisture that has seeped through cracks in the external walls. Unlike rising damp, this can occur at any level of a building but is usually higher up due to other common factors. This includes:

Overflowing gutters
Missing roof tiles
Leaking pipes and downspouts
Covered air bricks

It can also be caused by poorly fitted windows and doors, cladding, flashing and render.

Typical signs of penetrating damp are growing areas of damp on walls or ceilings, blotchy patches, wet and/or crumbly plaster, spores and mildew, drips and puddles.

How can I stop the black mould?

While rising and penetrating damp requires a professional to stop the cause of it, condensation can be stopped quite easily.

Controlling ventilation and air circulation around the home is the most important step in the prevention of condensation, as this allows moisture-filled air to escape outside, preventing further problems.

If untreated, condensation can lead to damage to the property very quickly, such as staining/damaged wallpaper, wall surfaces and window frames; it can also damage your own belongings such as your furniture and clothing. The mould and its spores carry a musty smell but cannot grow where salt deposits are (unlike rising and penetrating damp).

The best way to deal with the mould it produces is to remove it from the walls using a special fungicidal wash (which should be used in line with the manufacturer instructions on the packaging). You can also purchase special paints to delay the return of the mould, but unless steps are taken to reduce condensation, it will eventually grow back.

How can I reduce the condensation?

There are 4 things to consider when dealing with a condensation problem – heating, insulation, ventilation and excess moisture.

Heating: Condensation is most likely to be a problem in underheated homes. Try to keep the temperature in all rooms above 15°C to reduce the condensation.

Insulation: insulating your home as much as possible will warm the temperature of the walls, windows and ceilings. This will also generally increase the temperature of the home and reduce heating costs. When renting, you can insulate the home without spending a fortune by putting things in like rugs and thicker curtains.

Ventilation: Condensation significantly decreases if you circulate the air in the home, as it will escape before clinging to the cold surfaces. Make sure your trickle vents are open and any external airbricks aren’t covered by bins or garden furniture.

Excess moisture: Take steps to reduce your moisture output as much as possible.

Tips for reducing condensation in certain rooms

In the living room and bedrooms

Open window trickle vents during the day or when you’re out, or open the window for at least 10 minutes per day
Wipe windows with a window squeegee
Insulate your flooring with thick rugs to keep the room warm
Hang thick, heavy lined curtains during the winter
Don’t put furniture like beds, sofas or wardrobes directly against an external wall, leave a gap for airflow

In the kitchen

Close internal doors whilst cooking and open a window to create an outside escape route for the steam
Use the extractor fan, and puts lids on pans (this also reduces boiling time and helps to save money)
Only boil as much water/liquid as you need to cut back on excess steam

In the bathroom

Open the window whilst washing/bathing and leave it open for 20 minutes afterwards where this is safe to do so
Use your extractor fan for every bath/shower
Take shorter, cooler showers during the summer months
When running a bath, run the cold water first. Let the hot water warm the cold water up, instead of having a bath full of steamy water seep into the room while it cools
Wipe down mirrors, tiles and shower doors with a squeegee to absorb excess moisture
Don’t leave wet towels lying around, and hang them outside to dry where possible

Did you know...?

A family of four can add moisture into the air the equivalent of 30-40 litres of water per week just by breathing.
Showering, cooking, bathing and washing can add 15-20 litres per week
Drying clothes indoors can add 10-15 litres per week.
Drying your clothes on the radiators makes your boiler work harder to keep the heat up, and can cost almost as much as using a tumble dryer – not to mention the excess moisture going into the air. Try drying them on a rack in a room with an open window instead; they’ll dry much quicker this way too.

Source: NEA Action for Warm Homes

Back