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Damp, mould and condensation

There are three main factors that cause condensation:

  • Too much moisture being produced in the property
  • Insufficient ventilation within the property
  • Controlling cool temperatures

You need to look at all of these factors to cure a condensation problem.

Condensation is warm moist air produced by normal household activities like cooking and bathing, it is always in the air even if you cannot see it. When warm moist air hits a cold surface such as a window or a cold wall condensation is generated.

When this happens on your window, the glass mists up and drops of water run down the window. When it happens on a wall, the wall soaks up the moisture and becomes damp. Mould could then grow on the damp areas.

Condensation usually occurs during cold weather and can be found in places where there is little air movement.

Look for condensation in your home on or near windows, in corners and in or behind wardrobes and cupboards. Condensation forms on cold surfaces and places where there is little movement of air.

Condensation can lead to mould growth, which can contribute to health problems for occupants such as asthma and other respiratory diseases.

As well as affects on health condensation in housing can also lead to the deterioration of building finishes and fabrics, which can lead to increased maintenance and management costs. Condensation occurs in cold weather, even when the weather is dry. It does not leave a 'tidemark' round its edges on walls. If there is a 'tidemark', this dampness might have another cause, such as: 

  • Missing slates or tiles from a roof
  • Leaking or blocked gutters
  • Leaking and blocked down pipes and overflows
  • Leaks form internal plumbing and plumbing appliances
  • Soil piled against the wall above the level of the damp-proof course

Condensation happens most on the cool parts of walls, particularly on outside walls where there is not much air movement. It often appears as a dark patch in corners near the skirting and on the ceiling. The side walls of windows are often affected as they can be even colder.

Areas with poor ventilation can also be prone to condensation. Areas such as this could be behind furniture, particularly wardrobes and beds if they have been placed against an outside wall.

Condensation can happen in any room but is most likely to occur in your bedrooms and hallway as they are cooler.

To tackle condensation, a balance of measures must be used including improving the insulation and ventilation in your property and making sure there are no cold areas.

Moisture production is influenced by the design, construction, disrepair of the property and also the number of occupants and activities undertaken within the property. 
In our experience, the majority of enquiries regarding damp and mould growth are related to a condensation problem within the property.

Condensation occurs mainly in cold weather, whether it is raining or it is dry, it does not leave a tell tale tidemark. It will appear on cold surfaces, such as windows, tiled areas, toilet cisterns, and areas of the dwelling where there is a lack of ventilation, and little movement of air. It often becomes a problem when mould growth appears. Black mould and mildew can grow on almost any surface including wood, silicone, tiles, floor coverings, paint and paper. When this happens a tenant will usually contact their landlord, or their local authority.

Moisture enters the air from everyday activities. Trying to produce less moisture in your home will help in attempting to tackling and reduce the problem.

Some simple changes in lifestyles and the occupation of properties can also help reduce condensation as well as being more energy efficient. Examples of these are;

  • Wipe away excess moisture from windows and windowsills ever morning and wring out the cloth rather than drying it on a radiator or in front of a heater to prevent the removed moisture evaporating back into the atmosphere
  • Dry clothes outdoors on a line where possible; if using a tumble dryer, ensure it is a condensing unit if not ensure that the vent is vented to the outside. If neither option is available put the clothes in one room to dry with the door closed ensuring that the window is open allowing excess moisture to escape
  • Cook with pan lids on and open kitchen windows or use the extractor fan when cooking. Turn the heat down once the water has boiled. Only use the minimum amount of water for cooking vegetables
  • Do not use your gas cooker to heat your kitchen as it produces moisture when burning gas
  • Open windows or use the extractor fan when coking, bathing or showering and keep the doors to the rooms closed. Once you have finished in the room leave a window open slightly to allow excess moisture to escape, and ensure the door is closed behind you
  • When running a bath, put cold water in first then add the hot. This reduces the amount of steam by 90%
  • To reduce the risk of mildew on clothes and other stored items, allow air to circulate round them by removing 'false' wardrobe backs or drilling breather holes in them. You can place furniture on blocks to allow air to circulate underneath. Keep a small gap between large pieces of furniture and the walls, and where possible place wardrobes and furniture against internal walls. Pull shelves away from the backs of wardrobes and cupboards. Never overfill wardrobe and cupboards, as it restricts air circulation
  • Don’t keep furniture and beds hard against walls, make sure air can circulate
  • Keep your heating on low throughout the day in cold weather
  • If you do not have heating in every room, you could keep the doors of unheated rooms open to allow some heat into them
  • To add extra heat to rooms without any form of installed heating, it is better to use electric heaters, for example oil-filled radiators or panel heaters, on a low setting. Remember, you should not use portable bottled gas heaters in homes suffering with condensation as they give out a lot of moisture whilst in use. It is actually cheaper to heat a room with on-peak electricity than by using bottled gas heaters
  • Ventilate your bedroom by leaving a window slightly open at night, or use the trickle ventilators if fitted
  • If you have trickle vents installed above windows, keep them open all the time. This allows air to circulate around the property
  • Don’t block air vents or air bricks, they are there to circulate air trough the property, blocking them prevents the moisture from escaping
  • Be careful not to 'over-ventilate' your home when it is cold, as it will cause the temperature inside your home to drop and make condensation more likely. It will also increase your heating costs

Condensation occurs on cold spots, so if you can warm up the cold spots you can reduce the condensation. 

Insulating your loft, external walls and draught proofing doors and windows will help to reduce cold spots and also help reduce energy bills as the home will be cheaper to heat.

Ensure your property has suitable cavity wall and loft insulation to reduce the number of cold surfaces where condensation can form. Older properties may require more work in providing additional insulation.

Provide safe and suitable heating in your property with timer and temperature controls. Ensure it is serviced annually and ensure that tenants understand how to use the heating system in your property.

Keep the property warm naturally. Don’t trap heat, avoid placing large pieces of furniture in front of a radiator this prevents the heat from circulating. Keep curtain length above radiator height as thick curtains can stop heat escaping. Remember to close curtains at dusk. Keep curtains open on sunny days to help warm rooms and keep doors open in rooms that get lots of sunlight, this will allow the warm air to circulate in your home. 

Try to avoid having cold areas in the home. If you have a condensation problem it is better to heat the whole home to a lower temperature, rather than one room to a very high temperature. When you get condensation forming it is often not in the room where you are making the moisture, for example, kitchens and bathrooms, but in a room you don’t often use, like a spare bedroom. This is because the room is usually not heated. Try heating rooms regularly. 

By providing suitable ventilation to the property this will allow excess moisture to escape. Special attention should be paid in rooms such as bathrooms and kitchens. Ensure that the windows in these rooms can be opened, and where possible, provide extractor fans. 
Ensure that occupants understand how to correctly use extractor fans, vents and opening the windows, and the benefits this can achieve. Ensure that existing air vents and air bricks are not blocked, or decorated over, and that trickle vents on windows and doors work correctly. 
You can also ensure that damp is not being caused by leaking central heating or waste pipes, defective rainwater pipes/gutters, drains, toilets or a failed damp proof course or defective rendering.

Mould can be easy to remove. You can normally wipe it off with a disposable cloth using some household cleaner. There is no need to use strong chemicals. Wipe over the area again every few days using diluted household cleaner to stop the mould growing back. This should become part of your regular cleaning routine.

In more severe cases where wiping areas down as detailed above is insufficient strip wall and ceiling paper from the mould affected rooms.

Wash down or spray mould-affected walls, ceilings and paintwork with a fungicidal wash (Mould & Mildew remover) that carries a Health & Safety Executive (HSE) approval number, and ensure you follow the instructions for safe use. These fungicidal washes are often available at local supermarkets or Do it yourself outlets. Follow the manufacturer’s instructions precisely. 

Dry-clean mildewed clothes, shampoo carpets. Do not try to remove mould by using a brush or vacuum cleaner as this can release spores and increase the risk of breathing problems. 

After treatment, redecorate using a good quality fungicidal paint and a fungicidal resistant wallpaper paste to help prevent the mould from recurring. 

The effect of fungicidal or anti-condensation paint is destroyed if covered with ordinary paint or wallpaper. Once the mould has been removed then you can deal with the basic problem of condensation to stop mould from reappearing.

The landlord does have a duty to provide adequate heating, insulation and ventilation to a property. As the law stands, landlords can only be held liable for condensation that has been caused by disrepair to existing items that he or she is obliged to repair. These should be listed in your tenancy agreement, but as a minimum these will be: the structure and exterior of the building; the services for the supply of water, gas and electricity; the installations for the disposal of waste and foul water; the installations for space and water heating.

If you are still experiencing issues with condensation and you have followed the above advice please contact us to see if further assistance can be provided.

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