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Simple Ways to Identify the Cause of Mould in your Home

Condensation, Penetrating Damp or Rising Damp?

So what is causing the damp and mould within your property?

Household damp is a major issue for the UK housing sector. It often leads to mould growth which can create severe damage to walls, skirting boards, flooring, windows and doors.  Thousands of pounds are spent on call out charges to fix damp problems within the UK annually.

The three most common causes of mould
within the home are:


1). Condensation related mould.

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This type of mould is created when warm moist air hits a cold hard surface like a wall, window or ceiling and the water condenses and gathers as damp on a surface.  It is produced mainly in kitchens & bathrooms where water is heated for things like cooking, washing up and bathing/showering. Condensation can also be produced from dishwashers, washing machines, drying clothes on radiators and from your breath. Did you know that we exhale approximately 2? pints of water a day which is why our windows are steamed up in the mornings on a cold day. Inadequate ventilation means that warm air cannot escape and condenses when it hits a cold surface.

Use this checklist to help identify if your mould is condensation related:

  • Does the amount of damp on surfaces increase when the weather is
    cold and dry outside?
  • Do your windows steam up on the inside?
  • Do ceramics such as tiles and toilet cisterns have moisture on them after cooking/bathing?
  • Do you have mould with fuzzy, soft edges and no surrounding water mark?

If you answered yes to most of the above questions and have mould nearby it is likely that the mould growth is caused by condensation. 

2. PENETRATING DAMP related mould.

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This type of mould is due to building damage or faults either in the walls, around windows, or via cracks in pipework and guttering.  This allows water to penetrate through walls. Some common areas include the roof, guttering, rain drainage and mains water. If you can identify a broken or defective plumbing or brickwork it can be repaired.  Whilst the damp can be lower down on your walls, if it is not going down to the floor this is a good indication of penetrating damp.

Use this checklist to help identify if your mould is caused by penetrating damp:

  • Is the damp localised and in a specific area?
  • Does the damp feel worse after heavy rainfall?
  • Is the damp on an exterior facing wall or window
  • Are there any visible cracks or damage to the building/pipework outside the house?
  • Is the damp located away from the base of the walls?
  • Is the damp above ground level?

If you answered yes to most of the above questions and have mould nearby it is likely that the mould growth is caused by penetrating damp.

3. Rising Damp related mould.
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Rising damp affects ground floors and is created from groundwater coming into contact with walls and floors. Modern properties will have some form of damp proof course or membrane which is usually visible on the outside walls of the house. Some properties may use a different material such as slate. Damp proof courses were made compulsory in London from 1875 onwards.  On the outside walls there will be a visible line along the brickwork on the lower part of the wall. If this has deteriorated or split from age or damage it can allow water to soak into the structure of your house.  Water can also find a way to creep up the wall above the damp course.  A damp course should also exist in interior walls but will usually be hidden behind plaster. Rising damp tends to travel along the wall from the base upwards and will typically produce a wave shape water mark along the wall.

Use this checklist to help identify if your mould is caused by penetrating damp:

  • Is there earth, soil or other material collected against the house which is above the damp
    course membrane?
  • Is the damp low down on the wall, starting at floor level and creeping up the wall?
  • Are there visible signs of damage to the damp proof course?
  • Is there a water mark around the edges of the mould?

If you answered yes to most of the above questions and have mould nearby it is likely that the mould growth is caused by rising damp.

Naturally there are a number factors that come into play in terms of the causes of damp in homes.  This guide is a starting point for looking at the likely causes. Please seek the advice of a qualified professional to confirm the root cause, or causes, of the damp in your home. It is possible that there are several issues and more than one type of damp present.

Condensation related mould is probably the biggest cause of mould in UK homes and there are effective ways to reduce this with a few simple measures.

See our other articles “Three Steps to Treat and Eliminate Condensation Related Mould from your Home” and “Top Tips to Prevent Condensation Mould in Winter” for more information.

Visit our shop for mould prevention guides with our information DVD and Booklet produced for Housing Associations, Local Authorities and Landlords as an educational guide for their tenants.  We also have mould treatment products including mould eradication packs, black mould treatments, mould treatment sprays for furnishings and our comfort thermometer which gives users an appropriate household temperature guide to reduce condensation.

Cause of mould

 

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