Damp patches 1 metre off of the ground

It can be very strange to find that you have damp patches in the middle of your walls downstairs. Paint doesn't dry and will eventually fall off, even if it is natural paint. Claypaint applied in these areas will be darker than elsewhere and clearly shows the problem. So what has caused this?

Basically what has happened is that cement render has been applied to the old wall when damp proofing work was done. The old lime plaster was hacked off to a level of approx. 1 m and then the new render and plaster applied. More often than not, the walls were not damp proofed. The thinking being that the damp will not travel that high, but it does!

The damp from the, normally non-existent,  foundations travels up the bricks until it can get out (this is where the new render finishes and the old lime one begins). Hence the damp patch. However there is some bad news as well.

The water brings with it natural salts and these gradually get deposited in the plaster. When concentrations get too high the paint will react and start to flake off.

The remedy?

Basically you need to get rid of the new render and plaster and put the old lime render back on, this will allow the moisture to disipate from the structure. You can also install a retro-fit damp proof course using a silicon cream (Ultracure and Dryzone are well known ones). This is a DIY job really.

The salt contaminated areas will also need to be removed as paint will not stick to this.