When temperatures drop and the windows stay shut, the water vapour we generate indoors condenses on the coldest surfaces: glass, frames and the corners of external walls. If you are wondering how to get rid of damp in a room, the first thing is to understand where it comes from, because in most flats it does not come in from outside: we produce it ourselves, every single day.
Where damp in the home actually comes from
A family of four can release between 10 and 15 litres of water into the air every day: breathing, showers, cooking, laundry dried indoors, watered plants. In summer that water leaves through open windows. In winter, with the windows closed and increasingly airtight frames, it stays inside.
Comfortable relative humidity sits between 40% and 60%. Above 65% the problems start: a musty smell, windows that never seem to clear and, a few weeks later, the first black specks of mould in the corners. A hygrometer costs very little and is the only way to stop guessing.
How to get rid of damp in a room in 8 steps
- Air the room briefly but intensively. Throw the windows wide open for 5 to 10 minutes, three or four times a day, ideally creating a cross draught. A window left ajar all day does exactly the opposite: it barely changes the air and chills the frames, where vapour condenses instantly.
- Act straight after a shower, after cooking or after running a wash. Air the room when the vapour is produced, not last thing at night.
- Keep the bathroom and kitchen doors closed. Otherwise the vapour spreads through the whole house and condenses in the coldest room, which is usually the bedroom.
- Use the extractor hood and put lids on pans. Cooking with a lid cuts the steam by more than half. Switch the hood on before you start and leave it running for a few minutes afterwards.
- Do not dry laundry in a closed bedroom. A single load is several litres of water evaporating into the air of that room. Far better in the bathroom with the extractor fan on or the window ajar.
- Do not switch the heating off completely in rooms you do not use. A cold wall is precisely where vapour from the rest of the house condenses. Keep it at 16-17 °C at least.
- Pull furniture away from external walls. Five to ten centimetres is enough for air to circulate behind it. A large wardrobe pushed against a cold wall is the classic spot for the first patch.
- Check the ventilation. Hold a sheet of paper against the extract grille: if it does not stick, there is no draw. Never block the grilles and, if your windows are very airtight, consider fitting trickle vents.
Dehumidifiers: when they genuinely pay off
A dehumidifier does not replace airing, but it helps where damp keeps coming back regardless: ground-floor flats, internal rooms or wherever you dry the washing. Compressor models perform well above roughly 15 °C; in a cold storeroom or garage a desiccant model works better. For wardrobes, pantries and small bathrooms, calcium chloride moisture absorbers are enough, although it is worth remembering that they only ease the symptom.
Mould on the wall: what to do and what not to do
Never scrub the patch dry: that scatters the spores around the whole room. Put on gloves and a mask, dampen the surface, apply a fungicidal product and ventilate during and afterwards. Vinegar removes the colour, but it does not reach the mycelium sitting inside the pores of the plaster.
If the patch comes back within a few weeks or covers more than half a square metre, the cause is structural: a thermal bridge, a leak or rising damp. At that point chemistry is just make-up and it needs a professional to look at it.
Condensation on the windows: what it is telling you
If the water appears on the inside face of the glass, there is too much moisture in the air: the answer is airing and heating. If the mist is between the two panes, the sealed unit has failed and no amount of ventilation will fix it; that one is a job for the window manufacturer's service team.
The habits that make the difference all winter
Damp comes back not because the cleaning failed, but because the old habits come back. Build a simple routine: cross-ventilation in the morning, the hood on whenever you cook, one single place for drying laundry and a hygrometer in the bedroom. Within two weeks you will see the difference in the reading.
And if you are getting the house ready before the cold sets in, our shop has home and pet accessories that help keep everything in order.