A New Damp Proof Course Will Solve Rising Damp

Most building materials which are used for walls are porous, that is, they will absorb water if they are in contact with it. This is because the materials are not solid, but contain many very small holes called pores and capillaries into which water can pass. As water spreads through porous materials it draws more water along behind it – even against the force of gravity – in much the same way that a kitchen towel will absorb a small spill of water if just one edge of it is dipped into the water.
This mechanism means that a wall in contact with the wet ground will absorb water and the water will also pass up the walls – this is rising damp. Rising dampness is the result of capillarity, this being the process in which water rises up the very fine tubes formed by the pores

As the water passes up the wall, it evaporates away from the surface at a rate mainly depending on the temperature and type of wall covering. Eventually, the amount of water passing into the wall is balanced by the amount which can evaporate and the water does not reach any higher up the wall. This may result in a tide mark being seen across the wall – below it, the wall is constantly damp, but above it is relatively dry. The height of the tide mark depends on the dampness of the ground and how quickly water can evaporate from the wall. If the wall is coated with a water-resistant covering, such as tiles, gloss paint or vinyl paper, the damp may reach much higher before it can evaporate. Rising damp rarely rises above a height of 1 metre above the external ground level and/or the internal solid floor level.

Often the rising water will carry salts into the wall from the ground. These can react with plaster or brickwork and a deposit of crumbly white crystals may be seen on the surface. They can be brushed off and may build up again, and affected plaster will eventually perish, becoming soft and falling off.
Rising damp can be most costly when timber floors are affected. In older houses, floor joists are often seated directly into walls, with little or no protection from the dampness. Joists are usually supported directly on to the physical damp proof course in more modern building constructions. Where rising dampness exists, masonry, on which the timber joists are supported, becomes wet. Eventually, damp wood will become infected with wood-decaying fungi such as wet rot or dry rot, and may also become attacked by wood-boring beetles. These cause a complete breakdown of the structure of the wood and the floor may eventually collapse. This can occur over a short period, or take many years, depending on the degree and speed of development of the dampness and the resultant fungal or insect attack.

Treating Rising Damp – Damp-Proof Courses

Old buildings were constructed with little or no protection from rising damp, but in more recent times rising damp has been prevented by inserting a layer of water-proof material into the wall as it was built. This was often slate, poured bitumen or bituminous felt, but nowadays is most likely to be a layer of PVC. Although some of these have a long life, it is possible for these substances to perish and allow water through. This is not the case in modern PVC damp-proof courses.
Luckily, it is possible to damp-proof most buildings without dismantling them. The only truly effective method used today is chemical injection DPC.

Chemical Injection DPC

This method involves drilling holes into the wall at approximately 100 mm intervals and injecting a chemical into the wall until the wall material is soaked with the chemical. The chemical layer then controls water rising past it.
Chemical injection is quick, easy and efficient, with no mess or fuss. The job can be completed and a 20 Year Guarantee Certificate signed off on the same day. In most cases a price can be given over the phone or in response to an email enquiry.
Whether your buying or selling a property or just want to live in a damp free home, contact Dampwise Medway today.
We offer the quickest and cheapest solution to rising damp in the South East.