DECEMBER 13, 2016 | BY Perthshire Property Services
Condensation advice

At this time of year we have a lot of tenants contact us with regards to water on their windows or black mould spores appearing.  In the majority of cases this is due to condensation.  Hopefully this guide to condensation will help to reduce any moisture build up in your property.  

Condensation is caused by water vapour or moisture from inside the dwelling coming in to contact with a colder surface, such as a window or wall. The resultant water drops (condensation) may then soak into the wallpaper or paintwork or even plasterwork. In time, the affected damp areas then attract black mould that grows on its surface.

Condensation mainly occurs during the colder months, whether it is rainy or dry outside. It is usually found in the corners of rooms, north facing walls and on or near windows. It is also found in areas of little air circulation such as behind wardrobes and beds, especially when they are pushed up against external walls.
Note. Black mould is frequently seen on this type of dampness.

Condensation and Mould Growth
Most homes will be affected by condensation at some point. However, certain activities can increase the problem. Whether you are an owner occupier or a rent-paying tenant, condensation and mould growth is
often due to habits and lifestyle and is something that can be reduced or remedied by the occupant.

Cooking, washing, drying clothes indoors, even breathing - all produce water vapour that can only be seen when tiny drops of water (condensation) appear on colder surfaces such as walls, windows,
ceilings or mirrors.
The ‘amount’ of condensation in a home depends upon three factors:
1. how much water vapour is produced by the actions of its residents
2. how cold or warm the property is
3. how much air circulation (ventilation) there is
Simply turning up the heating will not sort out the problem, this may only temporarily reduce condensation. All three factors may need to be looked at to reduce the problem.

The first sign of a problem is water vapour condensing on windows and other cold surfaces, which then takes a long time to disappear, allowing surfaces to become damp. The second indication is black mould
patches growing on these damp areas.

Common household moisture producing activities
Our everyday activities add extra moisture to the air inside our homes. Even our breathing adds some moisture. One person asleep adds half a pint of water to the air overnight and an active person adds twice that rate during the day.

The illustration below gives you some idea of how much extra water you could be adding to the air in your home in a day:-
2 people at home for 16 hours 3 pints
A bath or shower 2 pints
Drying clothes indoors 9 pints
Cooking and use of a kettle 6 pints
Washing dishes 2 pints

Warmth versus Ventilation
Striking the right balance between warmth and ventilation is important and can be very effective.
By opening windows or ventilating your home it may appear that you are losing some heat, but what you are actually doing is allowing warm moisture-laden air to escape and permitting cool dry air to enter your
home. Dry cool air is actually cheaper to heat than warm moist air! Many people who have double-glazing installed experience problems with condensation and mould growth that they never had with their old draughty window frames. This is because all the natural draughts around the poorly fitted windows have been sealed. However, by using trickle vents or opening windows slightly, then the necessary ventilation can be achieved.
Remember - The advice is to ventilate for an appropriate period of time,not to leave the windows open all day.

Black mould
Mould spores are invisible to the human eye and are always present in the atmosphere both inside and outside dwellings. They only become noticeable when they land on a surface upon which they can grow and then multiply.

For mould to thrive and survive it requires four elements
1. Moisture - obtained from condensation
2. Food - such as wallpaper or emulsion paint
3. Suitable temperature - courtesy of the householder
4. Oxygen. - courtesy of mother nature

By dealing with the causes of condensation you will automatically deal with the problem of mould.

Dealing with black mould
Black mould can grow on walls, ceilings, furnishings and even on clothes and toys, which can be depressing and expensive.
To kill and remove the mould:
a) Carefully remove excess mould with a damp cloth and throw away after. Or if possible use a vacuum cleaner and empty after. Do not brush mould as this releases spores into the air.
b) Wipe down affected areas using a fungicidal wash or diluted bleach – remember always use rubber gloves and wear safety glasses.
c) Tea Tree oil is a natural antiseptic and disinfectant but it’s also great for cleaning especially on mould or mildew. Try a dilute of three to four drops of Tea Tree oil in two litres of water (hot or cold). Soak mildewed items in the solution or spray on to trouble spots using a plant mister. Wipe, then rinse off. Always ensure you carry out a test on small area of the fabric/material/surface beforehand.

Dealing with condensation is not easy. Only carrying out one or two of the above steps may not solve your problem. You need to do as many as possible every day, so that it becomes part of your habits and

Six Steps to Reducing Condensation and Black Mould Growth
A six-step plan can help to reduce the amount of condensation and thus
black mould growth in your home.

1. Produce Less Moisture
Ordinary daily activities produce a lot of moisture.  To reduce this:
a) Dry clothes outdoors. Avoid drying clothes indoors or if you have to, dry them on a clothes airer in the bathroom with the door closed and either an extractor fan on or a window slightly open.
b) Vent tumble driers to the outside (never into the home) or buy a condensing type.
c) Cover pans when cooking and do not leave kettles boiling.

2. Remove Excess Moisture
Always wipe the windows and window sills of your home every morning to remove condensation. This
is especially important in the bedroom, bathroom and kitchen - just opening the window is not

3. Ventilate to Remove Moisture
It is important to remove condensation and excess moisture by ventilating rooms. You can ventilate a room without making draughts or causing it to become cold. To do this, you may only need to open the
window slightly or use the trickle vent that can often be found on new UPVC windows. This allows warm (but moist) air to escape to the outside and let in cool (but dry) air.
a) Always ventilate or open a window when using the kitchen or the bathroom and close the doors to prevent moisture in the air from spreading to other parts of the house. Continue to ventilate these rooms for a short time after a shower, a bath or cooking, and keep the door closed!
b) Open bedroom windows for up to one hour as soon as you arise and throw back the sheets or
duvets to air the bed and bedding.
c) Clear window sills of clutter that will restrict opening the window.
d) Leave space between the back of furniture and cold walls.
e) Ventilate cupboards, wardrobes and avoid overfilling them as this prevents air circulating.

4. Heat Your Home a Little More
In cold weather, the best way to keep rooms warm and avoid condensation is to keep low background heat on all day rather than short bursts of high heat when you are in the house. Heating controls on your radiators, room thermostats and a timer will help control the heating throughout your house and manage costs.

So remember the essential tips - 

  • Heat and ventilate
  • Put lids on pans when cooking
  • Dont dry your clothes inside
  • Dry down your windows in the morning
  • Dry down your showers after use
  • Heat and ventilate!!!