What is Rising Damp?
Rising damp is moisture present in your walls as a result of water in the ground underneath or next to your walls rising up through the fabric of the wall, whether it be brick, block or stone. The water travels upwards through the wall as a result of capillary action (where water is sucked through a small opening such as a tube or hole) through the tiny holes in the brick or stone. The water stops rising at a height where gravity counteracts the upwards force of the capillary action. This ‘rising damp’ usually reaches a maximum height of 1.2m, but the effects of the damp, such as salt deposits, may be seen higher up due to the presence of non-breathing wall coverings such as vinyl wallpaper and non breathing plasters, renders and paints.
What are the Signs of Rising Damp?
Typical signs of rising damp rather than other damp problems are a ‘tide line’ of yellowish or brownish staining or blown plaster in the lower area of your wall above your skirting board. You also might have damp or rotting skirting boards or flooring. You may see white, fluffy deposits in your plaster – these are ‘salts’ which the damp has washed out of your bricks and into your plaster. Black spots of mould may also appear on on the damp areas of your wall.
A yellow or brown ‘tide line’ above your skirting board is one of the signs that you may have rising damp in your walls.
As damp evaporates from your walls it can leave salt deposits behind – these are another sign that you have a damp issue.
What Causes Rising Damp?
Rising damp problems often occur as a result of not having a Damp Proof Course installed or having a Damp Proof Course that is faulty due to age or inadequate installation. A Damp Proof Course is a waterproof layer in your wall (or both walls if you have a cavity wall), ideally about six inches from the outside ground on your external wall and under your raised timber floor or near your concrete floor on your internal wall (so both DPC’s are on the same level). This layer repels water – a variety of different DPC’s are available.
Remember that your damp problem may not necessarily be caused by rising damp – there may be another source of water that you are not aware of. A telltale sign that your damp is not rising damp is if the damp patches are higher up than 1 metre on your wall and are unevenly distributed, in which case you may be suffering from penetrating damp instead.
Get in touch and we will provide a free site survey and give you a written copy of our findings with our advice on how to rectify the issues. We are experts at dealing with rising and penetrating damp issues and have over 35 years experience within our team.
A damp proof course will stop rising damp from rising up into your walls – it is a waterproof layer that sits between your bricks across your house.
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