20 Feb Controlling Damp
Damp can be controlled in a number of ways depending on the nature of the damp problem, and its location.
All remedies with either eliminate the damp problem by dealing with the cause or by treating the symptoms.
Condensation can be tackled in two ways; by reducing the levels of humidity in the air and ensuring that surfaces are kept below the dew point temperature. Humidity levels can be reduced simply by opening a window or fitting an extractor fan, whilst indoor temperatures can be maintained at an adequate level with suitable heating.
If you are experiencing problems with penetrating damp make sure you repair and replace missing or damaged roof tiles, and clear gutters and rainwater pipes on a regular basis. Badly eroded mortar joints should be re-pointed using a lime:sand mix, which should not contain cement for buildings built before the beginning of the 1900s.
Below ground damp can be dealt with effectively by letting the property breathe. If the floor has a damp proof membrane that is redirecting moisture to the bottom of the walls it may be useful to replace this with a breathable construction or alternatively to allow a breathing space around the perimeter of the room. Replacing cement render with a lime-based mortar can also help by eliminating damp in walls and enabling rising damp to dry out. French drains can also be effective, preferably not sited directly against walls but with the use of rodding points.
Future problems can be avoided by using lime plaster to re-plaster interior walls rather than anti-sulphate or renovating plaster. To maximise breathability it is also useful to decorate with paints such as soft distemper and lime wash. If timber is removed during renovation it should not automatically be replaced but repaired and refitted if feasible.