Not all dampness is the same. That may sound obvious, but in practice it is one of the most commonreasons remedial work fails.
The three types I deal with mostfrequently are rising damp, penetrating damp and salt-relateddampness. Each has a different cause, presents differently, and requires a completely different approach. Getting that wrong does not just fail to resolve the issue, it often makes it worse.
Rising damp occurs where moisture is drawn up through masonry by capillary action. It is typicallyseen at low level, often forming a horizontal band or“tide mark”.While it is a recognised defect, it isalso one of the most over-diagnosed conditions in residential property.
Penetrating damp behaves very differently. It enters laterally through defects in the building envelope,such as failed pointing, cracked render, defective rainwater goods or poorly detailed openings. Ittends to present as isolated patches and will often worsen following periods of heavy rainfall.
Salt-related dampness is frequently misunderstood. In these cases, the original moisture source mayalready have been resolved, but hygroscopic salts remain within the plaster and masonry. Thesesaltsattract moisture from the air, giving the appearance that the dampness has returned when in fact it isa residual issue.
On inspection, these can look very similar. Without proper investigation, it is easy to draw the wrongconclusion.
In my experience, most unnecessary expenditure on damp treatments comes down to one issue, thecause was never properly identified at the outset. Once that happens, everything that follows is basedon the wrong assumption.
If there is any doubt as to what type of dampness you are dealing with, it is worth establishing thatproperly before any work is carried out. It will save a considerable amount of time, disruption and costin the long run.
