Rising Damp and Treatment


Simply put, rising damp is ground water rising up through the wall of a construction, absorbed by the porous building material. The upward movement of moisture through walls - and sometimes floors-happensvia a process called capillarity. In order to better understand this, imagine a sponge being soaked in any liquid: gradually, the liquid will start pushing upwards as it is absorbed, transferring moisture to the upper levels.

Rising damp can climb to a usual maximum height of 90cm on the walls, depending on the masonry types and outside ground levels. Olderproperties without appropriate waterproofing run a greater risk of developing rising damp problems. Moisture is natural and all buildings are surrounded by it, however, in places with higher relative humidity, like London, this can quickly become a problem.

Rising damp occurs only in ground-level floors. The ground water that is being soaked by the walls not clear and contains high amounts of salts and minerals that stay behind long after the water evaporates, leaving deposits of minerals on your walls.

The residue that remains after the evaporation consists of minerals that fall into two categories.

These minerals fall into two categories:

  • Non-hygroscopic sulphates, which appear as a flimsy layer of dust on the wall and are generally not harmful;
  • Hygroscopic nitrates/chlorides, that are the culprit for drawing more rising damp through the building material of a property, slowly corrupting it from the inside.

Rising Damp Symptoms

Some typical symptoms of rising damp on walls are mould, rot on the wooden frames or floorboards, and stains. Salt deposits will form a horizontal tide mark on your walls, below which there will be discolouration, peeling wallpaper and possibly white efflorescent salts which have been drawn out of the brickwork by the water. You will also notice problems when painting, as the paint will not stick to the walls. These symptoms are quite similar to the ones that show in penetrative damp problems, however rising damp can only occur on ground floors.

salts-buildup-through-bricks Floors can display moist patches and staining, while porous materials such as stone and brick will soak up moisture like a sponge without the aid of a damp proof membrane or rising damp treatment. When a building is constructed, a rising damp treatment is generally installed in the form of a damp proof course in the walls to prevent rising damp appearing. However, when this treatment does not exist or becomes damaged, the most common result is rising damp.

If left untreated it will rot any floor joists and other interior timber that come into contact with it, and will cause more damage to the interior of the property.

The Treatment for Rising Damp Issues

A new DPC (damp proof course) will need to be installed. This is achieved by removing all internal plaster and backing coats back to the brickwork at a minimum of 1,000mm, depending on exterior ground levels, to stop any chance of bridging the affected areas.

Drilling holes into the base of the wall at 120mm intervals and injecting Triton Chemicals new generation DPC formula. This is a water based Thixotropic gel, which diffuses naturally into the substrates. After injection, Tri- Gel reacts to form a water-repellent silicone resin network within the capillaries of the substrate. This network is permeable to water vapour which means that the walls can breathe and dry out naturally. This formulation is not reliant on alkalinity for effective curing. Tri-Gel can be used to treat brick, stone and other substrates.

Rising Damp Before After

Once the affected area has been injected a 3-1 sand and cement waterproof render is applied to prepared brickwork followed by multi finish plaster once the render coat has been allowed to dry out.

rising-damp-treatmentIt takes a professional to determine whether rising damp (or any other moisture-related problem) is a serious threat, so proper diagnosis is key to determining which course of action is suitable for you. We have the proper equipment, know-how and experience to tackle even the most extreme of cases. Contact Damp Proofing London today, to book your freeestimatevisit or send us a detailed quote and our qualified professionals will be happy to answer any questions!



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