Damp Proofing
The source of rising damp is the soil or subsoil. These are always wet, without moisture in them plants could not grow. But soil consists, in the main , or decaying plant material and bacteria, moulds and soil living animals. So soil water is not pure water, it is a dilute solution of the soluble materials to be expected from the nature of its source. Of these nitrogen containing salts are the most characteristic and chlorides are also generally universal. Rising damp is therefore a rising, dilute solution of various materials including nitrates and chlorides. When the water evaporates these are left behind because they cannot evaporate. Although rising damp is a slow process and the solution is dilute, continuance in a number of years results in quite high concentrations of certain nitrates and chlorides at the surfaces from which evaporation occurs .
