Last Updated: 01/12/2016
Author: Graeme Fisher Tags: Condensation
I have a leak in my property, sorry Sir it’s actually condensation! We often find there is confusion surrounding condensation and residents often misdiagnose the problem to be a leak from the building.
Condensation is a result of warm air from the building coming into contact with cold parts of the building for example with an external wall. A major cause of black mould growth within buildings is condensation. We provide below some useful tips on the reasons for condensation and practical measures that you can follow in order to prevent it from occurring.
Causes of moisture
Everyday living activities generate moisture within your property, on average a 5 person household puts about 10kg of water into the air per day without taking into account heating. For example:
• breathing (asleep) 0.3 kg
• breathing (awake) 0.85 kg
• cooking 3 kg
• personal washing 1.0 kg
• washing and drying clothes 5.5 kg
Without adequate ventilation within your home warm air becomes trapped and reaches its dew point on cold surfaces to form condensation. If black spot mould occurs this can be cleaned with a bleached based product however this does not deal with the underlying cause and the mould will simply re-occur at a latter date.
Practical steps to control condensation
In summary there are 3 primary measures that can be taken to prevent condensation
1. Increase ventilation: to remove moist air from the building and not allow it to come into contact with cold surfaces
2. Increase insulation: to prevent a cold surface reaching below Dew Point
3. Maintain consistent heating: to prevent the structure becoming cold.
• Leave some background heat on through the day in cold weather; most dwellings take quite a long time to warm up and it may cost you more if you try to heat it up quickly in the evening.
• After a bath or shower, try to ventilate the room to the outside, not to the rest of the property - just opening a window or the extractor fan and closing the door will help.
• Ideally, dry clothes out of doors; where this is not possible, dry them in a cool area of the house or flat. Whilst this will take longer, less moisture can be held in colder air and with good ventilation, the risk of condensation is lower.
• When people come in with wet coats, hang them outside the living area to dry.
• Try to increase the change of air in the premises - increase ventilation; trickle vents can be added to double gazed units.
• Add forced ventilation/extraction to areas which produce a lot of moisture (kitchens and bathroom). Extractor fans are available with an air-moisture switch so that they operate automatically while the moisture in the air is above a set amount. Other units called heat exchangers (more expensive/complicated) are available which remove the moist air and reuse the thermal energy within it which would otherwise be wasted.
• Consider using a dehumidifier. Domestic types are now available and can remove a surprising amount of water from the air.
• Don't overfill cupboards and wardrobes. Always make sure that some air can circulate freely by fitting ventilators in doors and leaving a space at the back of the shelves.
• Do not use paraffin or LPG heaters. They are probably not allowed in flats.
If condensation still persists there are other things to try:
• Simple secondary glazing consisting of little more than a sheet of glass (or plastic) screwed to the window frame with a seal in between can be fitted. This is relatively cheap. Fixed secondary glazing must not be installed on all opening windows in a room as some ventilation is essential. DIY kits are available which allow the secondary glazing to be temporary removed or opened to allow the original window to be opened for ventilation.
• Alternatively new double-glazing windows can be considered. Although much more expensive than simple secondary glazing, there are additional benefits; existing wooden or metal windows will need continuous maintenance and repair - with new double glazed windows, you get new window frames which will probably be low maintenance or maintenance free.
• Some decorative materials always have cold surfaces, (i.e. ceramic tiles, mirrors etc.) and are well known for the formation of condensation. There is not much you can do where this occurs other than keeping the room (and so the tiles) evenly heated throughout the day or improve ventilation.
• Some wall surfaces can also be a problem. Where the wall is papered the situation may be made worse if there are many layers of paper. This can just act like blotting paper. All the layers should be stripped and the wall re-papered.
• Things can also be improved by lining the wall with thin expanded polystyrene (normally available from a wallpaper stockist) before you hang new wallpaper.
• Painted walls can also have a cold surface. If you do not want to paper it, consider lining it with wooden paneling or another material such as cork tiles.
• Ceilings under the roof will suffer from condensation if the original construction of the block does not provide any roof insulation. If there is no or little roof insulation, additional insulation should be installed such as a false ceiling. For some groups of people, there are financial grants in the UK for such work - check with the Local Authority or advice centre for details. Additional insulation will not only reduce condensation, but also reduce energy loss and so save money.
• Where ceilings have a high gloss finish, consider covering them with expanded polystyrene, cork or fibre tiles; alternatively wooden paneling can be installed.
• Solid floors (like concrete) are often cold because of their large thermal mass - they take a long time to warm up. Even vinyl floor tiles tend to be cold. However there are warm flooring alternatives available such as cork or cushion tiles.
If you would like to discuss any of these matters please contact me, Graeme Fisher - Associate Director - Service Charge Department
Taken in part from ARMA lessee advisory notes LAN 17