A cellar always has a slightly higher humidity level than the above-ground part of a house. In a finished basement, the high humidity can be a problem, as wallpaper, carpets and wooden furniture can soak up the moisture and become damaged. Walls in damp rooms are particularly susceptible to mould.

 

The ideal humidity in a cellar room, as in the rest of the home, is between 30 and 50% relative humidity. Humidity that is too low dries out the skin and mucous membranes, while humidity that is too high can lead to mould, which is harmful to health.

Before finishing a cellar, you should eliminate all possible cracks in the walls and floor through which additional moisture can penetrate. A hygrometer can be used to measure the exact humidity in the room in question. In rooms with excessive humidity, you should install a dehumidifier, a device that automatically removes excess moisture from the air and collects it in a water tank.