You can access this information as a downloadable Fact Sheet, here: Damp and Mould

Excess moisture within properties can cause many problems, from increasing the chance of woodworm to increasing the chances of family members developing asthma. 

This is a guide to the main forms this moisture can take, together with suggestions for prevention and solutions.

CONDENSATION
Condensation occurs when moisture in the air within the property encounters a cold surface, such as a single-glazed window. The drop in temperature turns this moisture from water vapour (a gas) into water (a liquid). This can cause the appearance of rain down the inside of some windows in winter.

Condensation can be prevented by: 

• Heating all areas of the property at regular intervals, to reduce the amount of cold areas.
• Insulating the property and fitting double-glazed windows.
• Ventilating areas prone to damp (and making sure you use all present ventilation) to ensure as much water vapour as possible leaves the property.
• Preventing the excess moisture in the first place by leaving lids on pans while cooking, and keeping
  the internal doors to kitchens and bathrooms closed, as those are the rooms that tend to produce
  the most moisture in their normal use. Also, try to dry clothes outside. If you have to dry them indoors don’t place them directly on radiators.

RISING DAMP
Rising damp comes from moisture in the ground beneath the property, and enters through the property
where a preventative damp course is either faulty or not present. This form of damp is usually identified by the fact that it will be on the ground floor only, will be visible as a ‘tide mark’ rising up one or more walls, and will not usually exceed around 1m in height.

Rising damp should not be tackled in a DIY fashion; a professional can confirm the cause and provide
a solution, usually in the form of a damp course installation/repair. It is likely that this will involve the
removal of plaster work, so redecorating will be required in the affected rooms.

PENETRATING DAMP
Penetrating damp enters the property from an external source, usually a crack in rendering/pointing, or perhaps via a faulty drain pipe diverting excess water at a weak point of the external wall. From within the property the damp is usually identifiable as

1. Damp marks appear during bad weather and disappear/reduce during dry spells,
2. The damp appears only on the inside of external walls, and
3. The damp marks correspond with damage to the building on the outside.

To resolve issues of penetrative damp, an appropriately experienced person should undertake the remedial work to the outside of the property. The damp marks on the inside should fade over time. It may be necessary to redecorate.

If condensation or damp is left untreated it can quickly lead to the development of mould. This usually takes the form of little black dots on the affected areas (such as windowsills or frames, but also the backs of cupboards and wardrobes if there is insufficient heating and air circulation).

DEALING WITH MOULD
Mould can produce harmful spores, which can make existing respiratory problems much worse, so removing mould isn’t just about saving your wallpaper, it’s also essential for your health and wellbeing.

Upon finding mould in your property, the first this to do is to remove it by using a mould cleaning spray/liquid, which should be available at hardware stores or some of the larger supermarkets.

Make sure to follow the instructions carefully to ensure your safety and also to make sure you eliminate the mould correctly.

Now you’ve removed the potential cause of illness, the next thing to do is to tackle the underlying issue. It is vital you don’t skip this important step or the mould will likely come back and you’ll soon find that getting rid of mould has become a regular household chore.

For condensation issues, follow the steps overleaf. If the problem persists consult a contractor to investigate the matter more fully. For problems with rising and/or penetrating damp be sure to consult a contractor in the first instance.

Once your condensation/damp problem has been fixed you may have to redecorate to completely remove any sign of the issue.

VENTILATION

All properties require ventilation to allow air to circulate, reducing the likelihood of condensation and damp forming. However, there is no need for properties to be draughty.

Air bricks
These are the most common types of property ventilation and are installed in areas where airflow is
essential. These must always remain open to prevent condensation and/or carbon monoxide problems. A
gas safe registered engineer should be able to advise you in regard to the level of ventilation required for your heating system.
Window ventilation
Most modern UPVC double-glazed window frames have ventilation included as standard. This might be in the form of ventilation strips that can be opened or closed. Some windows have a “ventilation lock” facility that allows for the flow of air, while still preventing entry.
Draughts
Air coming into the property through cracks in floorboards, skirting boards coming away from the
walls, chimneys, letterboxes or ill-fitted doors and windows is not intended and not required. Most
hardware stores stock materials such as draught-proof strips or sealants that can be used to solve these
issues.

Consult a contractor if you are at all unsure about undertaking these works. If you rent your home you
should speak to your landlord as it is likely to be their responsibility to fix these issues.

DID YOU KNOW?
Bottled gas heaters can generate up to a litre of water vapour for every litre of bottle gas they burn.
This water vapour has to go somewhere. If you’re not careful it will turn into condensation, which can lead to problems with mould. Only use these heaters in well ventilated areas.