Having damp problems in your house can not only be unsightly and depressing but also foster mould and fungi whose spores are harmful to health, especially to those with allergies.
Damp walls can have two causes: rising damp and penetrating damp.
Penetrating Damp is where water from the outside of the house is finding its way through the wall. If you find damp patches on the inside of the wall check the outside – the roof for damaged tiles, that the gutters are not blocked with leaves or rubble, downpipes are not blocked or split and that your double glazing and windows and doors are sealed properly – all these can cause water to penetrate the wall. If you find the fault you can often repair it yourself by taking simple measures such as clearing out blockages or adding extra putty or sealer to your window and door frames.
Rising damp is where moisture from the ground penetrates the lower parts of the walls; usually there is a waterproof layer, a damp proof course-that stops the water from rising up the wall. Sometimes the ground outside the house has been raised for example if soil has been piled up against the outside wall of a house (perhaps a new flower bed) and breached the damp pro of layer. Dig it away. Old houses may have their damp proof courses broken or breached by, for example, rubble. A specialist damp proof fitting company is then needed to fit a new one.