Ground water contains soluble salts, the most significant of which are chlorides, nitrates and sulphates. When rising damp occurs, these pass with the water up the wall and are left behind when the water evaporates. Over many years of active rising dampness large quantities of these salts accumulate within the masonry and decorative surface, most becoming concentrated in a general ‘salt band’ towards the maximum height of rise as illustrated in the diagram on the left. Both chlorides and nitrates are usually hygroscopic, (i.e.they can absorb moisture from the surrounding environment) and, in general, the greater the amount of salts the greater the absorption of moisture - especially under humid conditions. Thus, even though rising dampness may have been controlled by the insertion of a remedial damp-proof course these salts alone can cause the wall and any contaminated decorations to remain damp. It is for this reason that specialist replastering is such an important aspect of rising damp treatment. Further information on replastering as part of a rising damp treatment
Treatment of Rising Damp
Treatment of rising damp (known as "damp-proofing" or "dampcoursing") typically involves the installation of a chemical DPC, such as Dampcheck Plususing specialist injection equipment, followed by replastering using aRefurbishment Plaster or a salt retardant render incorportaing Renderguard Gold. However, with the introduction of Dryzone Damp-proofing Cream, the process has now been simplified. The Dryzone system is based on a high-strength damp-proofing cream that is injected into holes in the masonry without the need for an injection pump.
