If left untreated, damp can cause serious harm to your home and even your health. According to the World Health Organisation’s latest research into the effects of dampness and mould, you are also at a 75% greater risk of developing respiratory symptoms and asthma if you occupy a damp or mouldy house.
James Allen, of Kenwood Plc, the leading damp proofing, woodworm and dry rot specialists, says: “The cause of damp varies but penetrating damp and rising damp are common problems. If you think you have a damp problem, the best thing would be to do a damp survey to find out what’s going on. We would normally advise getting two or three surveys done to compare the results.”
Rising damp – Rising damp is caused by moisture moving up through porous materials like bricks through capillary action. This normally occurs when the house does not have a damp proof course (DPC) installed, or it has broken. A DPC is a layer of plastic, slate, or other waterproof material placed horizontally between brick layers near to ground level. This acts as a barrier to stop moisture travelling upwards. “The most economic way of fixing a DPC,” says James, “Is to drill into the walls around ground level and fill it with a damp proof injection.”
Penetrating damp – Penetrating damp is caused by a problem with the exterior of your home. “Spotting it is common sense really,” James explains, “If you have a leak in one area, you go outside and check to see what is going on”. For instance; your roof may be leaking, or guttering and pipes may be broken, therefore exposing the outside walls to constant torrents of water.
Condensation damp – Condensation is normally caused by simple things we all do every day in our home such as running hot water, cooking or drying wet clothes on a radiator. All these things produce hot air heavy in moisture, which becomes trapped in your home if it’s not well ventilated. When this air settles on a cold enough surface, such as a window or wall, beads of water are formed (condensation). As James points out: “All new houses have to be built with proper ventilation systems in them, usually in the bathroom and kitchen to avoid mould growing because of condensation.”
If you have a damp house, walls might feel wet and cold to the touch or you may see watermarks on the ceilings or walls caused by salt deposits. As James explains: “With rising damp, the moisture rises up by capillary action and carries with it salt, which is hydroscopic (it attracts moisture which, along with oxygen, can cause erosion). This can cause major damage to plaster work.”
Sometimes damp can result in moss or mould growing on your walls or ceilings and even on furniture and curtains. A good way of spotting penetrating damp is to look for green moss outside your home: “Anywhere you see green moss growing, for instance in the junction at a gutter, indicates fresh water running,” says damp proofing specialist James.