Damp can be caused by various factors, many of which can be prevented by good maintenance. Prevention to stop damp will always be cheaper than methods needed to fix damage, although unfortunately sometimes it is too late.
Damp problems can occur anywhere that is exposed to moisture such as rain, external gutters and water pipes that run throughout the property
There are three main types of damp, all of which are a result of different causes;
This form of damp is caused by moisture getting into the property by passing through ceilings, floors and walls. This will often be caused by a plumbing defects, leaking roof coverings or rainwater goods, guttering etc which can be either internal or external defects and may cause extensive damage to plaster, timber and joinery. Other forms of penetrative dampness may relate to high ground levels or abutting structures where moisture ingress can occur.
Rising damp occurs due to moisture from the ground which can pass into the masonry unless an effective barrier is present. Many older properties did not contain any damp proof course and more recent properties where a damp proof course was provided, may suffer from defects over time, often resulting from problems of ‘bridging’, high ground levels or damage during renovation works etc.,
When a property becomes damp and starts to deteriorate, there is risk of further decay to the property affecting internal aspects such as plaster, skirting boards or floors and this is the primary concern with rising damp. When rising dampness occurs, the moisture from the ground contains ground salts, which are deposited within the plaster and hence renewal of the wall plaster is normally required to overcome the effects of the salt in the masonry.
Over 20% of homes may be affected by condensation damp making it the most common form of damp occurring. The cause of condensation damp is water vapour within the property being unable to escape and then condensing onto colder surfaces.
If a room has poor ventilation and especially if there is consistent temperature change in a room, such as the heating being turned on and off, water droplets can begin to appear on walls and windows which will then lead to the growth of a dark mould and musty smell.