Buildings have incorporated damp proof courses since the early 1900’s . This is to protect against the natural tendency of water in the ground rising through the pores of building materials (capillary action).
If the dpc fails for some reason, or was not present originally, then walls can become wet and affect internal plaster finishes.
Correct identification of the cause of dampness in walls is important. (Condensation, for example, can sometimes be mistaken for rising dampness and can be a problem caused by lifestyle choices as much as defects in the building).
And correct understanding of the cause is essential to ensuring that the remedial works are appropriate. There is no benefit injecting a new dpc, for example, if the problem is caused by high ground levels on the outside of the wall – reduce the levels and let the wall dry out. Likewise, there are occassions where it is necessary to insert a new dpc and replace previously wet plaster.
Correct diagnosis and remedy become even more sensitive when dealing with older properties or those of unusual construction. Although techniques are improving and changing, a holistic approach is usually the best, based on a sound understanding of how older properties work and of the materials used in their construction.
Water and most buildings do not represent a great mix. Rising dampness along with other forms of dampness within the building fabric are seldom welcome. So, early assessment and appropriate repairs are the order of the day.
Be sure to take advice from a surveyor or professional who understands the type of property in question. When you use a contractor, they should be registered with the PCA (Property Care Association).