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As surveyors, we see a lot of properties suffering from damp. Not every case is detectable, but symptoms like condensation on windows, mildew in disused corners and mould creeping out from flaking wallpaper are common. While odd patches of moisture can be treated quite easily, if a building is riddled with damp might be structurally unsound (timbers and brickwork can succumb to rot), and black mould can cause severe health problems for inhabitants.

Needless to say, the potential risks mean that even a hint of damp can put people off buying a property. So what should you do if you spot damp in your home-to-be? Well, the first thing would be to commission a property survey to uncover the extent of the problem. From there, you can decide whether the level of damp is something you can work with, or if you would prefer to find a drier home to move into!

Why does condensation happen at home?

Condensation can appear in properties of any age, and is usually caused when warm air, filled with moisture, hits a cold surface (like a window). Cooking, showering and drying clothes all adds to this moisture, and droplets are most likely to be spotted around windows or skirting boards on outer walls, where the water can begin to rot the wood.

The key to tackling it is to regain control of a room’s humidity, which can be done through the proper use of an extractor fan. Alternatively, a dehumidifier can be brought in for a quick, short-term fix. You should also ensure each room is well-ventilated. Opening the trickle vents around your window will help, but more complex systems like a heat-recovery ventilation unit or positive input ventilation can bring a greater supply of fresh air into the building.

Finally, improving the insulation around affected areas should keep the walls and windows a more balanced temperature and reduce the amount of condensation released.

What if the problem is worse than condensation?

Mould and mildew tend to be more problematic than condensation, not least because of how quickly they can spread.

Mould and mildew both appear when there is excess moisture in the air (so will typically go hand-in-hand with condensation on windows or other cold surfaces), and come from airborne spores. Low quantities of spores are generally harmless, but if they land in a damp, dark corner they can start growing very quickly. Most cases of mould are accompanied by a musty odour, lingering dampness and allergy-like symptoms in those that are living in the building (sinus congestion, coughing, skin irritations etc.).

As with condensation, dealing with mould and mildew involves reducing the moisture in the air and improving the ventilation around the house. Keep curtains open to let sunlight in, and make sure frequently damp areas are allowed to dry out thoroughly. If you regularly dry washing in the same area or have your bed pushed against the wall it might be a good idea to sporadically change this to prevent nearby walls from picking up excessive moisture.

Small patches of mould or mildew can be easily cleaned using a mixture of bleach and water (make sure to wear rubber gloves and a dust mask), but larger areas may need specialist attention. The important part is making sure the area is dry once you have finished cleaning, to ensure regrowth doesn’t occur.

Tackling the cause of damp

To eliminate the damp and its symptoms for good, you will need to identify how moisture is getting in the building. If better ventilation and temperature control don’t clear up the problem, look for damaged brickwork or broken guttering that is letting outdoor moisture in. Leaking pipes can also be the cause, as can external landscaping that has risen above the building’s damp-proof course (DPC).

If you can’t find the source of the damp then you may benefit from getting a specific defect report, or a full Building Survey to identify where the problem is coming from and the most effective way of fixing it. In the majority of cases, a damp home shouldn’t stop your sale. However, you should always seek professional advice to make sure you’re not walking into a crumbling money pit.