You’re probably more than a little confused by the question posed in this title, right? After all, a surveyor has told you there’s evidence of rising damp in your home and now you’re keen to get it fixed. You’ve even seen the evidence: rusty nails in your skirting boards and a telltale salty ‘tidemark’ on your wall where the damp has risen, then evaporated.
Yet many well-qualified professionals, among them architects, surveyors and conservators of heritage homes, robustly maintain that there’s no such thing as rising damp. Instead, they claim, these signs are the result of penetrative damp or condensation. This scepticism reached its apogee in 2008 when The Rising Damp Myth, a book written by qualified bricklayer Jeff Howell, was published.
But before we can analyse the veracity of the claims made in this book, we must first look at what rising damp actually is.
What is rising damp?
Rising damp is a diagnostic term given to the slow wicking of water up the walls of your home by capillary action. The water will rise until the forces of gravity overcome those of capillarity—at just over a metre from the ground—at which point the rise will stop. Moisture at the leading edge of the rise will then begin to evaporate, leaving behind the salts previously dissolved in it: this forms the characteristic ‘tidemark’ of rising damp.
Damp progressing up walls is a phenomenon observed as early as Roman times, and its prevention is exactly why builders began to incorporate damp proof courses into buildings.
So what is the evidence against rising damp?
The cornerstone of the argument against rising damp seems to be that a brick pillar standing in a tray of water in Jeff Howell’s laboratory did get wet but didn’t show any sign of wicking the moisture upward. Howells explains this by asserting that the cement- and lime-based mortars used to build the column prevented the rise of damp by capillary action. He claims that these observations also constitute definitive evidence against the existence of rising damp outside the lab.
What is the evidence in favour of rising damp?
It’s pretty easy to see the fatal flaw in Howell’s argument: his failure to replicate rising damp in the laboratory means nothing beyond the fact that his experiment was inadequate at replicating rising damp in the laboratory. And while the notion that rising damp is a myth has captured the imagination of some people, it goes against the experience of many specialists working in the field of damp proofing. Finally, and most compellingly, the concept of rising damp is compatible with predictions based on physics and is readily observable in cities around the world: go to Venice and you’ll see salty tidemarks on nearly every wall.
Rising damp exists
The Building Research Establishment (BRE), a former UK government agency, is unequivocal in its conviction that rising damp is a reality. In the opinion of London Damp Company, the controversy over this subject only serves to highlight the importance of a careful and correct diagnosis made by experienced professionals. So when you find that we offer a guarantee of 100% effectiveness for the diagnosis and treatment of your damp problem, you’ll understand our commitment to protecting your home from damp.
