Rising Damp Problems

Risingdamp01.jpgRising damp is probably the most well know form of damp problem that home owners have to contend with. As the name suggests, rising damp comes up into the building from ground level. Once dampness has penetrated the wall structure it rises up through the pores of the brickwork, or other building material, by a process known as capillary action. This is the same process by which moisture will rise up a paper towel if the bottom edge is suspended in water.

The speed at which rising damp will penetrate up through your walls depends on several factors. The type of wall and floor structure, the nature of the ground and the environmental conditions, both inside and outside the building, will affect the rate at which the problem spreads. Generally the progress of rising damp is quite slow and it may be many months or even years before the condition makes itself known by the appearance of peeling wallpaper, blistering paint, damp patches and rotting timbers. The sour, musty smell of decay is often one of the first signs that you have rising damp.

rising-damp-graph.gifWhen new buildings are constructed a layer of damp proof material, known as the Damp Proof Course (DPC), is fitted into walls about 15cm to 20cm above ground level, creating a horizontal barrier which prevents moisture from rising in the walls. This normally takes the form of a thick layer of PVC laid between the third and fourth courses of brickwork. It is when the integrity of the DPC is compromised, or it is broken, that rising damp occurs. With modern building regulations rising damp is largely, although not exclusively, restricted to older properties. For this reason although it might be the most well known form of damp problem, it is not the most common.

Rising damp can also sometimes start out as penetrative damp. For example, if building work adjacent to a house changes the ground level to higher than the existing DPC, water can get into the side of the walls. However, once the damp is in the walls and starts rising due to capillarity it is referred to as rising damp.

rising-damp_01.jpgThe most common cause of rising damp problems is through faulty ground or surface drainage. This is a growing problem, particularly in heavily built-up areas like London, as more and more ground area is concreted or tarred over and runoff from rain is unable to flow directly into the drainage system.

Dampness in houses can often be a combination of rising and penetrative damp and is often complicated by condensation problems. Once the dampness has taken hold the following symptoms may occur:


  • Dampness on wall surfaces, particularly in conjunction with condensation, promotes the growth of moulds. Moulds can grow not only on the surface of the wall, but also in the fibres of wall coverings and abutting carpets. This can become a significant health hazard as well as being aesthetically undesirable and expensive to replace.
  • As water evaporates from damp patches they will leave thick crystalline deposits of soluble salts, both on the surface and within the pores of the wall. The flower shapes that this forms are known as efflorescence and this is both unsightly and can cause structural damage.
  • High humidity is the ideal environment for many decay organisms, including wet rot, dry rot (ironically), weevils and wood worm. These organisms can cause considerable damage to skirtings and bonding timbers at the base of walls.


If you see any of the above symptoms, or notice any signs that rising damp may have affected your property, the first thing to do is to call in the professionals and get a free, no obligation quote to assess the extent of the dampness and help you decide on a course of action to remedy it before too much damage is done.



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