Damp walls in buildings can generally be divided into 3 main catagories, each caused by a different phenominum. The categories are rising damp, penetrating damp and condensation.RISING DAMP
Rising damp is the upward movement of ground water through the pores of a permeable masonry wall via a process called capillarity. Capillarity is the same process that enables the movement of water from tree roots to tree tops via intricately stacked hollow cells despite the counteractive force of gravity
Rising damp typically occurs if the built-in damp proof course is bridged, for example by a change in ground level, or if the damp course is damaged, for example by a structural alteration or a chemical reaction. In such cases rising damp may become a problem if it is likely to affect vulnerable materials or finishes that are in contact with the wall. For example if the damp has potential to rot joists, skirting boards or the bottom of door frames or if it causes wall plaster or wall coverings to deteriorate or become damp stained.
Modern damp proofing products include effective, environmentally friendly and easy to use damp proofing creams that can be used by a general builder or a competent DIY enthusiast to line the pores along a stretch of masonry wall with a silicone resin water repellent to form a new DPC.