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How to Stop Condensation on Walls and Windows

As a property developer, Stella has written many articles on the home environment, decor and problems that arise in the home and garden.

Run Cold Water First to Avoid Condensation!

Open the window when running hot water

Open the window when running hot water

Don't Get All Steamed Up About Condensation!

Bathrooms and kitchens in residential property often suffer severely from the results of condensation and should never be draught proofed due to being areas of high moisture production. Those unsightly black mould patches caused by water vapour in the air proliferate under such favourable conditions and may even be wrongly blamed on the structure of the building. In order to solve the problem it is first necessary to learn a little about how black mould is such a common occurrence in the home. It is nothing whatsoever to do with disrepair or a lack of cleanliness but it is everything to do with excess moisture.

Black Mould Accumulates On Window Sills Especially In Bathrooms And Areas With High Moisture Levels

Mould thrives in moist conditions caused by condensation.

Mould thrives in moist conditions caused by condensation.

Condensation Is A Lifestyle Issue

Condensation is a lifestyle problem caused by inadequate ventilation; moisture in the air is unable to escape from the interior of a building. Condensation is often mistaken for damp but genuine damp is almost always caused by water ingress from the outside through leaky roofs, faulty guttering or rising damp or penetrating damp through the walls from some outside source. Black mould hates outside-water which is too salty as it has come through the bricks from the exterior. Ordinary water stains are usually brownish orange or rusty in appearance and are never associated with black mould growth.

In order to keep bathrooms free from damp and mould caused by condensation, homeowners and tenants alike need to understand a little about what condensation is before blaming the structure of the building or the landlord. Wherever warm, moist air meets a cold surface such as glass on windows, mirrors, walls, tiles etc. condensation is caused. As the warm air cools, it can't retain moisture and condenses into droplets which settle on cooler surfaces. Look at your bathroom mirror when the room is steamed up from running hot water and you will see this occurring. Open bathroom windows when running your bath or taking a shower so the effects will be reduced. Even running cold water before the hot can reduce the amount of steam produced.

Black Mould Often Occurs Behind Furniture And In Corners

A Bad Case Of Black Mould Caused By Condensation

A Bad Case Of Black Mould Caused By Condensation

Removing Black Mould

Prevention is always better than cure but in the event that you do spot some black mould appearing in your home then the problem is not difficult to address. Mould and mildew spray can be bought cheaply from most supermarkets nowadays and with a bit of elbow grease, you will soon be rid of the mould without the need for further treatment. When cleaning with mould and mildew remover, bear in mind that this contains bleaching agents so remember to protect your hands and face and cover any nearby furnishings and carpets. For those areas such as bathrooms and kitchens where the mould keeps coming back, it might be an idea to purchase a mould inhibiting paint the next time you redecorate or buy an additive which you can mix into a can of ordinary paint.

Condensation Explained

Ventilation, Ventilation, Ventilation!

The key to prevention of condensation is adequate ventilation. Although double glazing and loft insulation are viewed as standard nowadays to keep homes warm in cold climates, they can also create condensation problems due to poor air circulation. Wherever there is little or no ventilation and stale air, condensation will likely occur. With fuel costs at an all-time high, homeowners naturally want to preserve interior heat but this can often be the primary cause of condensation. Houses aren't supposed to be hermetically sealed but this is what happens when there's little or no ventilation in the home.

Condensation rarely occurs during the spring or summer but is commonly associated with the winter months of October to March when proper ventilation of residential property is prevented because householders don't want to lose precious heat. Conserving heat this way is counter-productive because you're effectively causing problems which will cost you or your landlord more money. Homes were never designed to be completely airtight. Water vapour needs to escape and not just that caused by running hot water. Even breathing can cause significant condensation so the more people and pets you have in your home, the more ventilation is needed, If your wallpaper is slightly damp and cold to the touch, the next sign will be the appearance of black mould in areas where there is little movement in the air such as corners of rooms and in bathrooms - this will generally be seen in the area above the shower. Mould can easily be removed with a spray that can be bought at most supermarkets. In bathrooms it's also advisable to use mould-inhibiting sealant around the bath and shower cubicle.

Never position furniture right up against outside walls in any room; leaving a small gap will allow air to circulate. Fit vents in cupboards which are opened infrequently. Condensation in the bathroom can cause problems elsewhere in the property even in locations well away from the bathroom itself. Moisture can accumulate on any cold surface if not allowed to escape through the nearest window and can easily cause mould which will damage the fabric of the building and personal items. You will find that natural items such as suede, leather and wool will be most affected. A distinct mouldy smell will soon become apparent in cupboards and drawers that are not often used.

Condensation in bathrooms can be minimised and avoided altogether with a little care and attention. Ensure the bathroom door is closed when bathing or showering so moisture does not affect other rooms and open the bathroom window every time hot water is run and for some time afterwards. Always use an extractor fan where fitted.

Whenever possible dry clothes outside or ensure any tumble dryer that is not self-condensing has a functional vent to the outside. All that moisture has to go somewhere if it is not taken away through a pipe - it does not just disappear! However cold it is, never cover up air bricks or vents that need to be kept open for safety reasons to allow sufficient ventilation for gas appliances. There should always be an air vent fitted in unused chimney breasts. Wipe away all visible signs of water accumulation on any flat surfaces such as window sills and vertical surfaces such as tiling once you have used the bathroom. Drying washing on radiators is another big no-no that will inevitably cause condensation.

As condensation is associated with changes in temperature try to keep your home at an even temperature all day and night. Many folks fail to realise, it's more cost effective to keep the heating on low all winter rather than to keep turning it on and off. Starting a boiler up from cold to heat stone cold radiators will in fact cost you more in fuel because the boiler has to work harder each time you fire it up and will also cause condensation problems you can do without due to frequent changes in air temperature. Practical application of the advice given will ensure that your home and belongings won't be blighted by condensation problems and you won’t get ‘all steamed up’ over issues so easily resolved.

Mouldy Quiz

For each question, choose the best answer. The answer key is below.

  1. What does black mould need to feed on?
    • Cheese
    • Moisture
    • Salt
  2. What time of year is the worst for condensation?
    • Spring?
    • Summer?
    • Autumn?
    • Winter?
  3. Which should you do to prevent mould growth?
    • Dry washing indoors on the radiators
    • Dry washing outdoors
    • Dry washing in your bedroom
  4. What causes black mould growth?
    • The landlord
    • Constipation
    • Condensation
  5. What should you do to remove black mould?
    • Complain to the landlord
    • Scrub with mould and mildew spray
    • Just paint over it
  6. Why should you open the windows for a short time each day?
    • To ventilate and get rid of excess moisture
    • To let mould eating moths in
    • To get rid of pet smells
  7. Is black mould caused by water leaks?
    • Yes, always
    • No, never
    • Sometimes
  8. How high should the heating be constantly set to in winter to prevent mould growth?
    • low
    • high
    • Medium
  9. Should you complain to your landlord about black mould growth?
    • Yes, this property is a disgrace
    • No, it's a lifestyle issue caused by me
    • The landlord won't take any notice...I'll inform the council
  10. What sort of Materials will black mould grow on?
    • Nylon knickers and polyester pants
    • Wool and natural fibres
    • Chintz cutains

Answer Key

  1. Moisture
  2. Winter?
  3. Dry washing outdoors
  4. Condensation
  5. Scrub with mould and mildew spray
  6. To ventilate and get rid of excess moisture
  7. No, never
  8. low
  9. No, it's a lifestyle issue caused by me
  10. Wool and natural fibres

Getting Rid Of Black Mould

© 2014 Stella Kaye


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