Different types of damp can affect a property in different ways, and it is important to identify the type of damp you have as soon as possible. There will be different root causes for the different types of damp and various ways of dealing with them.
Any type of damp can be harmful. The World Health Organisation (WHO) says, “Exposures to biological agents indoors are a significant health hazard causing a wide range of health effects. Dampness is a strong and consistent indicator of risk for asthma and respiratory symptoms related to indoor environmental conditions.”
The NHS says that damp and mould, which is often a symptom of damp, can also cause, or contribute to, allergic reactions, skin conditions such as eczema, and problems with the immune system.
Together with health issues, damp can also ruin decorations and furnishings, such as wallpaper and carpets, as well as plaster, woodwork, window frames, and other parts of the structure of the building. It can also get into clothes and other belongings, can create bad smells, and contribute to an unpleasant living environment.
Condensation is caused when moisture present in the warm air comes into contact with a colder surface, usually, but not always, a window or an exterior wall. This can sometimes be easy to spot because you may see droplets appearing on windows and other surfaces, especially when it is cold outside.
Improving the airflow within a property by fitting good ventilation is the best way to deal with condensation damp but there are also many other things you can do. Moisture is always present in the air but you can reduce the amount you create by avoiding drying clothes indoors, leaving lids on pans when cooking, and making sure that tumble dryers that are not self-condensing are properly vented. You should also try to ensure that the property does not get too cold by keeping the heating at an adequate level even when you are not there.
This type of damp is caused by groundwater rising up through the capillaries, or pores, of a wall or floor. It can be difficult to spot until it has taken hold, at which point you might notice plaster or wallpaper bubbling or discolouration along a horizontal band. These 'tide marks' are caused by the moisture evaporating when it reaches a certain height and can be a combination of water and salts. Other signs are skirting boards starting to rot, and a noticeable smell of damp.
The usual way to deal with rising damp is to have a barrier called a damp-proof course or damp-proof membrane installed.
Penetrating damp gets into the walls or other structures from an external source. It could be rain water getting in through cracks in the wall, missing roof slates, or too much water for the walls to deal with, due to a blocked or broken gutter or water pipe. If it is found at ground level, penetrating damp can be mistaken for rising damp, although it tends to spread horizontally rather than climbing vertically.
Penetrating damp will usually show as damp patches, which get worse when it rains, but serious cases may drip or run. It is essential to identify and rectify the problem that is allowing the water to penetrate in the first place.
There will sometimes be areas of damp in a new-build house or after major renovations or building works. This is caused by moisture working its way out of the structure. It usually shows as patches, especially on bare plaster but can also appear on other surfaces. These may grow before shrinking again, sometimes over a period of months. Time is the best way to deal with this type of damp, and it is also generally the least harmful and damaging.
Whatever the cause of your damp, it may be necessary to get rid of the damp that is already present before tackling the root cause. Dehumidifiers or airing the house may be enough in some milder cases but another technique, such as a whole house ventilation system might be required in others. As well as treating the symptoms you also have to deal with the root causes, however, otherwise, the problems will return.
If any of the above conditions sound familiar but you are unsure what to you need to do next call us on 0345 27 27 807 and we can put you in touch with one of our local ventilation specialists who can discuss your problems and provide helpful advice on what steps you need to take. Alternatively, if you would like to arrange for someone to come and look at the problem then you can book a free home survey where we will come and check the damp issue and recommend the best solution available.