Despite its infamy, rising damp is a relatively rare problem, and will only occur if one or more of the following circumstances are present:
Damaged or Missing Damp Proof Course
Many properties have a slate or bitumen membrane barrier installed approximately 150mm (6in) above ground level in the ground floor section of the wall to prevent rising damp. This is called a Damp Proof Course or DPC for short.
Unfortunately, these DPC’s can fail due to age, deterioration, or damage caused by factors like subsidence. Modifications to a building like an extension or conservatory that have been built without a damp proof course also increase the risk of rising damp.
A Bridged Damp proof course
A new installation like a flowerbed or new driveway can raise the ground level and bridge the DPC. Essentially this means that your rising damp barrier has been skipped over and the groundwater now has direct access through to the porous building materials straight into your home again.
Damp-proof courses can also be bridged if debris in a cavity wall piles up above the height of the DPC.
If you cannot identify any of the above but you still have damp problems, then it is more likely that you require another damp proofing service for penetrating damp or condensation treatment.