Condensation is possibly the biggest cause of misdiagnoses of rising damp. Condensation is far more common than rising damp. Condensation is an increasing problem is both modern and older properties. This caused by a combination of modern lifestyles and the need to conserve energy/fuel services.
A simple explanation of condensation. Warm air will hold more moisture than cold air. When the warm air is laden with mositure this in itself does not cause a problem. The problems start when the air starts to cool down. As the air cools down it can not hold the moisture, so when it comes into contact with cold surfaces the air will shed the moisture in.
The obvious places for condensation to occur are on cold walls and floors, but it can also occur in roof spaces and in sub floor areas where there is a timber suspended floor. In the latter cases, it can lead to dry rot or wet rot developing in floor and roofing timbers.