After surveying a property that seemed to have high moisture readings, particularly to the lower areas of internal walls, I was asked by the Managing Director Michael Holden the question ‘does rising damp exist? ’, therefore I have done some in depth research into the matter and wrote this article to share my findings, exploring the claims of both sides of the debate.
Rising dampness is one of the most talked about debates within the Surveying profession. ‘Rising dampness’ is considered to be one of the main causes of dampness that can affect a building, the others being penetrating dampness and condensation. Rising dampness is said to be the upward movement of moisture through capillary action, however the legitimacy of rising dampness is questionable and much research has been carried out in the past to verify whether rising dampness truly exists. In a lot of cases (as seen in the images attached), internal dampness does give higher readings on moisture meters in lower areas of internal walls and there are often visible tide marks seen on walls. However, the main question regarding the matter is what causes this dampness within the lower reaches of internal walls, is it truly ‘rising dampness’ or are there other explanations for this phenomenon?
One of the most interesting observations I have come across whilst researching rising dampness is that rather than it being a common worldwide issue, some countries largely have remedial works in place (e.g. The UK) and some countries largely do not (e.g. The USA), this is an eye-opener and leaves the question behind, have we been sold a con? Or is rising damp truly a widespread issue that is in need of specialist remediation?
Firstly, there are those who rubbish the claims of rising dampness, studies have been carried out in the past that seem to back up these claims e.g. filling the cellars of buildings with water and studying the effects. Consequently, if rising damp is a myth, this means alternate sources of dampness that cause higher moisture levels within the lower levels of buildings must exist. There is said to be an array of potential alternate damp sources, to list some that I have come across; penetrating dampness lower levels of buildings, high external ground levels, poor drainage surrounding buildings, surface run off and internal condensation. It is claimed that a combination of these causes can give higher moisture readings to the lower levels of buildings, therefore destabilising the theory of rising damp. As well as this, it is claimed that the symptoms of rising damp consist of; flaking paint, crumbling plaster works and dark patches on walls, however these are also the symptoms of any form of dampness whether it be condensation or penetrating, therefore it is said to be almost impossible to truly identify rising damp even if it does exist. Those who rubbish rising dampness promote air flow and ventilation of buildings to reduce dampness within the home as oppose to more expensive remediation techniques.
The other side of the argument however, suggests that moisture can rise (as mentioned previously), as part of a capillary action, simply meaning water rises up a building in the same way water is soaked up by a sponge. Those who argue against the legitimacy of rising dampness therefore ask why rising dampness does not continue to rise up the building to the higher reaches, although those who advocate rising dampness argue that moisture can only rise so far up a wall before gravity takes affect and the water returns to ground level. There is also the debate of material, some building materials are claimed to ‘absorb’ more moisture than others hence why rising dampness is not seen in all buildings.
Both sides of the debate give reasons why rising damp may or may not exist, so to give a definitive response to the question ‘does rising damp exist?’ it is difficult. After looking at the evidence myself I know myself which side of the debate I am leaning towards for sure, however I will leave it to you the reader to decide for yourself if you believe in it or not.