Causes of rising damp
Rising damp affects properties when water prevention materials fail or are missing altogether. The most traditional materials to prevent rising damp in structures are damp proof courses or damp proof membranes. The combination of ageing, building movements or ground movements can cause damp proof course to crack allowing water to enter the structure.
Damp proof course can also fail due to careless construction and in particular when new extensions to building are added or thermal insulation is carried out. The most frequent causes are raised ground level, external rendering or internal plastering.
Another common problem are wall ties, which should have a central drip to stop water crossing the wall cavity.
Although not very frequent but nevertheless occurring failure is accumulation of construction debris at the bottom of the cavity wall. Mortar accumulated at the bottom of the wall cavity can bypass the installed damp proof course causing rising damp.
Remedies for rising damp
Traditional solution to rising damp problem would include installation of a new damp proof course of various types, all of which will however require stripping of the walls of plaster. Less demanding solution is the reduction of the problem rather the complete elimination. This could be achieved by construction of water drains around the property to lower the water table, clearing of the drains making sure they are not constantly soaked in water and to replace moisture and mineral loaded finishes with more moisture tolerant materials.
The most permanent solution is physical insertion of a new damp proffer course. Unfortunately it is a labour intensive and time consuming process which makes this permanent solution quite expensive.
Damp proof course can also be reinstated either by chemical injection of water resistant solutions (silicon or aluminium stearates) into the wall material or by installing a solvent free Damp-Proofing Cream which is becoming ever more popular. The least popular is of so called electrical damp proof course which involves positive electrical charges to counteract capillary action.