The common causes of damp in old houses are:
- Leaks – Water has got in from outside through, for example, a leaking roof;
- Non breathable materials have been used, for example the building has been re-pointed using cement based mortar;
- Condensation – caused by insufficient ventilation (often due to “improvements” such as new double glazing)
- Ground levels too high outside the building, causing damp to penetrate the wall.
Damp is rarely caused by “rising damp”. Most “rising damp” is actually caused by a combination of the above factors.
If you have a damp problem, it is vital to find out what is going on before rushing into costly solutions like damp proof courses, which are rarely effective. Many so called “damp experts” are merely sales representatives of companies which will be only too happy to sell you a damp proof course.
If you have had a survey on an old house and your surveyor has recommended that a “specialist damp survey” be carried out, do pin him down as to what he has found rather than letting him pass the buck like this! Not all surveyors are knowledgable about old buildings and sadly you will get better advice reading pamphlets on the internet from conservation organisations than talking to some surveyors.
We are not surveyors ourselves but can give you contact details of surveyors who genuinely understand the causes of damp in old houses.
See our pages on breathability and lime mortar for more information about what could be causing damp problems in your home.