Whether it’s rising up from the ground or coming down from the roof, damp is not something you want in your house – and not something you can leave unattended as the consequences can be severe.
These can include damaged furnishings and ruined clothing, the need for expensive structural repairs and, worst of all, ill health as a result of inhaling the spores of moulds that can easily grow in rooms and cupboards that are both damp and poorly ventilated.
However, most damp problems can be solved relatively easily if tackled early, and that winter, being the dry season in most of the country, is generally a good time to do this.
It is essential, though, to establish the real source of the problem, and to get some expert advice if necessary, before you attempt any repairs. For example, while damp at the bottom of exterior walls is usually ascribed to rising damp, this only describes the movement of moisture in a particular direction and does not address the possible causes.
These could include raised external ground levels against outside walls (where the ground is higher than either the physical horizontal damp proof course or higher than the internal finished floor level); plaster or other renders applied to external walls that bridge the damp proof course and are in contact with the ground, or even a high local water table. Consequently, simply putting in a new physical or chemical damp proof course may not actually be the answer.
Similarly, damp patches appearing inside your home can often be traced to an exterior problem. A wet patch at the top of a wall may well be due to a leaking gutter outside while a wet ceiling is most often due to a roof leak. However, the floors, windows, doors and pipework inside and outside the house are all potential causes of damp.
What could be an even bigger problem, especially in terms of mould growth, is poor ventilation and condensation in rooms with high humidity, such as kitchens, bathrooms and laundries. You need to address this as soon as it becomes apparent but fortunately, the remedy is often as simple as installing an extractor fan to vent excess humidity to the outside, and/ or opening windows to allow natural ventilation around your home whenever weather conditions allow.
Meanwhile, he says, those who are lucky enough to have no damp problems and would like to keep things that way should regularly check that roofs and flashings are waterproof; clear and repair gutters and down pipes; repair any cracks in the walls; make sure airbricks are unblocked; check that there are no plumbing or geyser leaks and insulate exterior pipes to prevent them from freezing and possibly bursting in winter.