rising damp treatments

The Top 4 Rising Damp Treatments

Water ingress is an inevitability. And for property owners it’s also an ongoing struggle, akin to a magician’s plate-spinning routine: just when one problem is fixed, one of the other structural weaknesses will start to teeter.

Whether you live in a farmhouse or a block of flats, the potential for damp looms large. For the latter (save for the upstairs neighbour leaving their bath taps running) condensation, and rainwater would be the main worries. For the homeowner, it’s all of the above - the full-house, as it were.

In this blog, we shall concentrate on the full house. What is rising damp exactly? It’s the common term given to the upward movement of groundwater in the lower sections of walls.

The process is known as capillary action (think of ink rising up blotting paper) and is characterised by a "tide mark" on affected walls.
The tide mark is caused by salts contained in the groundwater. When the water evaporates, the salts will crystallise, causing plaster to deteriorate.

With water continually creeping upwards, the situation will perpetuate and worsen.  Depending on the circumstances, wallpaper might peel; wood will become damp and rot. Moreover, a damp wall will lose more heat than it would otherwise.

It’s perfectly possible that the property already has damp proofing. For example, older houses tend to deploy a layer of slate between the brickwork, while modern houses include damp-proofing in the form of a synthetic damp proof course (DPC), about 15 cm above ground level.

Both serve as a barrier through which water cannot pass. Well, that’s the theory! The reality, however, is that a damp-proof course can be broken or incomplete, which allows moisture to find a way in. This is known as ‘bridging’.

All of this is, of course, the result of our inclement climate. But there are other factors that may hasten the moisture’s collection and progress. Poor drainage, for example, (check crawlspaces and/or the basement for standing water) or that the ground level next to an external wall might have been raised over time. Air bricks might now be blocked, and the ground level might now stand above the original damp-proof course.

So how is rising damp treated? It depends on the severity, and each case is unique. Leading examples of the rising damp treatments which Danford Brewer & Ives offer are:

  • The removal of surrounding soil or bridging material to a minimum of 150mm below the existing damp-proof course;
  • Injecting a chemical damp proof course or in some instances an electro-osmotic system;
  • Replacing any damp or rotten flooring;
  • Removing and replacing any plasterwork, skirting boards, radiators etc. if necessary.

A note of caution: we cannot stress highly enough the competence and experience of the person(s) investigating the problem. Misdiagnoses can and do happen; if the wrong form of treatment is administered, the chances are that it will have a little overall effect.

For example, salts left by rising water might cause plaster to yield; however, the heat from a fire can also cause salts in masonry to crystallise. As such, any damp proof course work in that particular area would be completely unnecessary.

At DB&I, we insist that our surveyors have the industry-standard Certificated Surveyor in Remedial Treatments (CSRT) qualification. (From 1st January 2018, this has been re-named Certificated Surveyor of Timber & Dampness in Buildings (CSTDB), yet it continues to be recognised as a professional qualification for surveyors in the property preservation industry.)

If you have any queries – whether it’s about treating rising damp, damp proofing or any of the other building services Danford Brewer & Ives offers, such as timber treatment, basement conversions, extensions or building maintenance – then please contact us. As ever, we’d be delighted to hear from you.