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Damp problems: how to recognise and prevent them

Damp problems: how to recognise and prevent themA comfortable interior climate has a relative humidity of around 50 percent. If it is drier or more damp, this may result in health complaints. Damp, in addition, will soon damage furniture, decoration, and even the constructional quality of a building. But how to prevent this?

Causes of deviations in relative humidity

There will always be some moisture present in the air, both inside and out, both in winter and on a hot summer’s day. In addition, the inhabitants of a house affect the relative humidity. People breathe and perspire, thereby giving off moisture to their environment. Their daily habits, such as doing the laundry and taking a shower, will add litres more to this. It is normal for a human being to add between ten and eleven litres of water a day to their surrounding atmosphere.

If the relative humidity is too low, this will irritate mucous membranes, resulting in stinging eyes and a dry throat. Too high a relative humidity is very unpleasant as well. And if the interior climate is damp, house dust mite and mould will increase. If people are sensitive to these, they will develop complaints to their bronchi. And the house itself will also suffer. Mould will attack walls and stucco, the wallpaper will come off, and floor joists will start to rot.

Measuring the relative humidity

Measuring the relative humidity in a room is done by means of a hygrometer. It will indicate how much water vapour is present in the air at any moment, compared to the maximum humidity possible at that temperature. The maximum is one hundred percent, the minimum is zero. A pleasant interior climate has a humidity of around 50 percent. To find out whether your home has a damp problem, you may easily determine the relative humidity in different rooms, at different moments. There are different types of hygrometers, such as electronic ones that operate on semiconductor crystals. A simple - yet just as effective - method is to use a hygrometer with two thermometers, one of which containing a tiny wet ball. Even a degreased human or animal hair to which a voltage has been applied may show the amount of water vapour in the air.

Signs of deviating levels of relative humidity

A damp problem may be recognised in various ways. For example by discolourations on the walls, a musty smell around the house, or windows that remain misted up for a long time. Another sign is the bugs that are rampant in a damp environment. Problems often occur in basements and crawl spaces, especially if the groundwater level is high.


The first thing you can do to prevent or reduce damp problems is to ventilate. Open a window or turn on the fan after having taken a shower, turn on the cooker hood when preparing a meal, and make sure to air sleeping and living rooms every day. Depending on the weather conditions, the inflow of fresh air will considerably reduce the relative humidity. Where the construction of a building is concerned, insulating your home will contribute to an improved moisture regulation. Note that this will further emphasise the importance of ventilation! If you doubt whether you are taking the right measures, please ask a specialist. You may also want to consult your proprietors’ association. Their website may possibly have a home ventilation test. If you are a tenant, you may approach the owner of your home. 

Adjusting the climate yourself

To achieve a favourable interior climate, the humidity should be balanced at around 50 percent. Because it tends to strongly fluctuate according to the weather conditions outside and the activities carried out inside your home, you may want to consider an air dehumidifier or air humidifier. A dehumidifier will extract air from a room and cool it down. This will cause water vapour to condensate, which is collected. Warm, dry air is subsequently blown back into the room. In relatively wet rooms, such as a bathroom or laundry room, this is a good way to simply control the moisture climate. Other rooms that may benefit from a dehumidifier are hobby rooms and bedrooms, which are often rather cool. A humidifier, on the other hand, will add moisture to the air. This may prove beneficial in rooms containing musical instruments or vulnerable works of art.

Air dehumidifiers and air humidifiers

Air dehumidifiers by Qlima will deal with damp problems effectively. They can be used either with a reservoir or with a permanent drain. The different models may be equipped with a system that filters out pollen and dust particles from the air. This way, they will contribute to a healthy interior climate. The built-in hygrometer will automatically monitor the relative humidity. Qlima air humidifiers introduce minute particles of moisture into the air in order to improve the air quality. The devices have been provided with a hygrometer and most models are equipped with a timer.