What exactly is Rising Damp?

Think about water moving upwards from the ground and through the walls of the property, this is referred to as rising damp. The water goes up through the pores in the holes in the masonry walls and a process that is referred to as capillarity. Capillarity is an electrochemical process where moderate water molecules are pulled towards mineral surfaces which allows the water to move upwards through the porous spaces against the forces of gravity.

At some point, the water will stop rising when it reaches a certain height that is no longer affected by the capillary action and gravity takes over. The maximum height we have seen in past instances has been 1.2m; however, the resulting effects of the damp when it comes to salt deposits can actually reach further heights. This is important due to non-porous wall decorations or coverings such as the non-wallpaper, plasters and paints.

If the building does not consist of DPC or retrofit works, the capillary action of water rising up through the masonry walls can happen over time. If you have plaster covering your walls it may make the effect of popping and crumbling as a result of this capillary action. You may also notice damp or moist spots and patches of discolouration on interior walls and this can eventually lead to mould or even worse situations.

Imagine a straw that is sucking up water, that imagery best describes what happens in the capillary action. The groundwater gets sucked up through the masonry walls and small openings in the bricks or stone. It’s quite typical that most walls will allow some water in; however, with the lack of DPC there is nothing that prevents this capillary action.

If your damp-proof course is lower than the level outside your home then rising damp can also be a problem, as this allows for water into the damp-proof course. If your property has materials such as brickwork, stone or plaster, these are all porous and absorbent materials and can be subject to rising damp.

Essentially rising damp is water deposits captured in your walls from rising groundwater. The tiny halls, also referred to as the porous material, in or on the porous structure of brick or stone, allows for this capillary action to take place.

One of the causes behind the Rising Damp

As we discussed before, rising damp is the effect of groundwater rising up through the walls and through small tubes or holes in porous materials like stone brick and other types of masonry. If you are the owner of a modern property, chances are these houses or buildings will be equipped with damp-proof course as a form of rising damp prevention. However, there are some exceptions where rising damp can still take place regardless of DPC. The following are some instances where rising damp can happen:

The absence of DPC or damp-proof course installed can cause rising damp. However, if you do have DPC, poor installation or deterioration can also lead to rising damp. DPC refers to a sort of waterproof layer within your walls, cavity wall included, and this layer is usually about 6 inches above the ground on your external wall and below your timber floor or concrete floor on your internal wall.

What signs should you look for if you have Rising Damp?

If you have suspicions that rising damp may be a problem in your property, there are signs that can answer your questions or concerns. One of them are black spots which are indicative of mould, and that may appear in patches along your wall.

Identifying rising damp is or can be so simple that one can do so without any professional equipment or qualified industry professionals to confirm. You can simply get your answer by looking or running your hands over the wall. Look for things like dampness or moisture, the growth of mould and even discolouration around the lower part of both the outside and inside walls.

If you are looking at the inside part of the wall you should pay attention to the height of 1m above the ground floor level. You may notice the blistering or bubbling of your plaster. This is or can be a sure sign of rising damp. If you are still unsure, a Southern Damp Proofing-qualified surveyor will be able to identify if the damp is from rising damp or from an alternative problem such as condensation from penetrating damp.

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