Moisture in the air will form condensation (droplets of liquid water) when it comes into contact with a cold surface such as a window. We all get condensation on our windows from time to time, but this isn’t necessarily a problem if it clears up quickly.
Problems start if the water builds up to the point where it starts to cause damage. And if it’s building up somewhere other than on the window, you may not notice until the wallpaper starts to peel, or black mould starts to grow. This is most likely to happen in places that are colder than the rest of the house, such as exposed corners or where there is a gap in the insulation, and where the air can’t circulate freely, such as behind furniture.
If you do have mould growing, it’s good to clean it off straight away to minimise any health risk, but you also need to fix the underlying damp problem to stop it coming back. If you don’t have any leaks or rising damp issues, then the problem is almost certainly condensation. There are several things you can do to help avoid problems in the future:
- reduce the amount of moisture produced in the first place by keeping lids on pans when cooking, drying clothes outside when possible, and if you use a tumble dryer, making sure it’s vented to the outside
- ventilate so the moist air leaves the house – always use the extractor fan when you’re cooking, showering or bathing, leave any window vents open, and don’t block off any other vents
- make sure air can circulate by leaving gaps between furniture and the wall
- try to avoid cold spots – if there’s a gap between your wall insulation and your loft insulation, for example, try to get this fixed as it will attract condensation and possibly mould
- consider adding more ventilation – this could be a new external vent in a problem corner, a new extractor fan, or even a whole house ventilation system if you need it
- don’t fit any new draught-proofing in a room that already has a condensation problem, and if you’re getting a professional to fit insulation, draught-proofing or new windows or doors, ask them what they have done to check that ventilation will still be adequate
If you experience condensation dampness in your home, watch our video explaining how you can reduce it.