What is Rising Damp?
Rising damp is when moisture from the ground travels up the walls of your building via capillary action. Not only does this make the walls damp but it will also suck in salts and impurities which can damage the structural integrity of the wall, especially if you have lime in the walls. The water will only travel so high as eventually the force of gravity will counteract the capillary action.
How do you identify rising damp?
Rising damp can be difficult to see until it has travelled quite far up the walls, especially if you have skirting boards. If the damp is severe you may notice the skirting boards start to warp, bulge or come away from the wall itself. If it is less severe you won’t notice anything until it has raised above the level of the skirting board.
The first thing you may notice is a yellow/brown stain that looks like a tide mark, this is the level that the moisture has reached so far, it may not be too obvious in the early stages, but it is a clear indicator. If this isn’t present you may still have bulges in your plaster board, flaking paint work or peeling wallpaper. If you use durable paints such as Kitchen/ Bathroom or washable paint you may fine little bubbles will appear in it, but it won’t flake. It is much harder to identify when using non-porous wall coverings such as durable paint of vinyl wallpaper. If you do have flaking plaster or paint one, clear indicator that it is due to raising damp will be salt deposits left behind when the moisture evaporates.
Check out these images to see if it looks like what you have going on.
How can you treat rising damp?
The first thing you need to do to treat rising damp is remove any wall coverings and skirting board, so you can see the extent of the damage. Then you need to identify if it is rising damp you have. If the water marks are more than one meter above the ground, then it is unlikely you have rising damp, and you probably have a leaking water source that you’re not aware of. If you’re not sure what type of damp you might have you can check this guide.
If you are sure it is rising damp and are confident you can carry out rising damp treatment, then you will need to remove all of the plaster work and check your damp proof course and membrane, repair or replace the membrane and/or damp-proof course (Houses built before 1875 are unlikely to have anything in place), you can then coat the walls with a damp proofing liquid to prevent damp occurring again, this can be a pricey option though.
If you are not confident that you can identify and repair the type of damp you have the it is highly recommended that you get a professional in even if it is just to identify the best rising damp treatment for you. Such professionals can carry out a visual and electronic inspection and provide you with details of the best course of action for repair offering you peace of mind that you are not wasting money treating the wrong problem.