A damp home is not a pleasant place to be. For one, the dampness can start to affect the interior of your home. Wallpaper can start to peel off the walls for example, as the moisture within the room starts to work on the paste holding your wallpaper up. Wooden furniture can start to warp and change shape, potentially causing permanent, irreparable damage. Unsightly damp patches can start to appear on walls. Slowly, a damp home becomes less and less enjoyable to live in and requires more and more care to maintain. More importantly there are also health concerns. Dampness and the black mould fungus (Aspergillus spp) that normally comes with it have been shown time and again to increase the severity of all manner of health problems. Just a few of the health risks caused by a damp home can include chesty coughs, running noses, sore and reddened eyes and difficulties sleeping. A damp house is not a healthy house.
The most common causes of damp in the home are:
Probably the most common cause of damp in the home is condensation, which can result from all manner of activities that put moisture into the air. Often the main causes are inconsistent temperature, insufficient ventilation, drying laundry indoors, not opening windows when using the bath or shower, cooking and insufficient extraction of humidity. Problems with condensation are typically far more common in winter when the colder weather means fewer open windows and other sources of ventilation. In this way the moisture in the air remains trapped within the building.
When the warm, damp air hits a cold surface the water vapour turns back from gas into liquid form. While it is most common to find condensation on windows and mirrors, in more extreme cases the water molecules may even be found condensing on cold wall surfaces, particularly behind large items of furniture.
All buildings are in contact with the earth around them. As this ground typically contains moisture, and both brickwork and mortar can be quite porous, there is a risk that damp from the earth surrounding your walls (and even floor) may slowly work its way up your walls by capillary action.
Whilst rising damp was a major problem in the past, these days the problem is seen far less commonly. This is because most properties built over the last few decades now have a properly-installed damp proof course, designed specifically to stop rising damp. However we are far from eliminating rising damp altogether as some older properties still don’t have a damp proof course and today’s changing climate can therefore turn a minor annoyance into a serious problem in a very short space of time.
Alternatively some more modern home owners have discovered to their dismay that while their property has a damp proof course, it has been incorrectly installed or bridged by a new patio or driveway. In this way, problems with rising damp can still occur, even when a property seemingly benefits from an existing damp proofing solution.
As the name suggests, lateral penetrating damp is dampness that travels in the “side”. Imagine the scenario of a house that is built with a damp proof course but over time the level of the floor inside the building and the soil outside shift, so that some of the soil is actually above the level of the floor. Alternatively a house may have been deliberately built like this, such as in the case of basements and cellars that are, by very definition, below ground. In these cases, moisture from the soil can transmit its way across the surface of the wall, causing severe damp and damage inside.
In more modern properties, many damp problems are caused by rain penetration where some form of building malfunction is allowing rain to access the inside of your property. Examples of such causes may include incorrectly installed (or no) cavity wall, a leaking roof or rainwater goods, defective external rendering or pointing or defective joinery You might imagine that rain penetration is easy to diagnose but that isn’t always the case. Sometimes rain can enter a property through a tiny gap that has slowly worsened over the months and years. In some cases the problem is only discovered when it has developed to a serious level.
Whatever the source of damp in your house it is essential to diagnose and repair the problem as soon as possible. Problems very rarely if ever resolve themselves and in almost all cases some form of professional remedial work will be required, and the sooner this gets done the smaller the job is likely be.