An experienced damp investigation surveyor will carry out an internal inspection of the property, and also an external inspection. On the external inspection survey they should be looking for possible problems relating to the internal problems and any other obvious defects. One of the most common problems is high external ground levels where the damp proof course has been bridged, or potential splash over the damp proof course.

Complete Preservation carry this type of work out normally using the typical drawing below. Normally we reduce the ground level externally by 150 mm this will also prevent rain splashing off the ground over the top of the damp proof course. We use specialist Hilti dust extraction systems connected to professional cutting equipment to minimise dust.


Below are some pictures of cutting and breaking out the 2photo 1photo 3

Geo-membrane is placed above the earth to stop weed growth and golden gravel is poured on top

photo 4

The picture below shows the level of what the ground level used to be before we lowered it, the sub floor vent was blocked which we cleared out.


This is very effective in helping evaporation of rising dampness at the wall base.

Posted by Complete Preservation


  1. I’ve had a survey carried out on a Grade II listed building. The survey states that the ground level around the outside of the house needs to be reduced to help reduce damp. As the building was built in 1850 and has no DPC I can’t see how this will help!!


    1. Hi Kevin,

      This is a sensible approach to allow evaporation at the base of the wall, also check for any other external defects especially when its raining. You may also wish to have a drain survey, if you continue to have dampness problems a survey should be carried out to BRE Digest 245.


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