Before

After

There is a common misconception that Rising Damp only travels 1 metre high. In fact the height that damp can travel depends on many factors such as the density of the brick or whether the evaporation of the water is only possible from one side.

A good indication of how high Rising damp has travelled is the white salt band that can sometimes be seen because the salts are carried with the water.

The ground salts carried up via the Rising Damp contaminate the wall plaster. As the damp evaporates, the salt migrates to the surface of the plaster and can sometimes leave a salt band.

These salts are sulphates, nitrates and chlorides.  The nitrates and chlorides are hygroscopic, which means they have the ability to absorb moisture from the atmosphere, where it will condense to form water. The wall plaster will always appear damp, although the bricks under the plaster may be dry. Sulphates are not hygroscopic but they can attack and break down cement. This is a real problem if sand and cement render has been applied.