Damp and moisture meters
A Victorian slate damp-proof course is bridged by a new path. Has the survey proved rising damp, or only the bridge?
Only the bridge. A Victorian slate damp-proof course covered by a new path is something the survey can see. The slate is meant to interrupt moisture climbing the wall, but only if it stays clear of the ground. A path built above that line wets the masonry higher up, so plaster can mark whether or not the slate itself has failed. A damp patch, even with a surface reading, does not by itself prove water is rising from below the course. The report records the bridge. It has not diagnosed rising damp.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Victorian houses often have a slate course a little above the original ground. A later path, patio or bed that sits higher puts brick or stone in contact with wet soil. Rain can then soak the wall above the slate and leave tide marks, salts or blown plaster. That pattern can look like rising damp. It can also be splash from a gulley or a leak at the downpipe. The survey has named the bridge. It has not opened the wall or traced a source under the floor.
Tell the solicitor the path is a visible defect and that rising damp was not proved. If the slate needs to be clear of the ground again, a builder can price lowering the path or forming a channel. That is not a treatment the survey has designed. A damp specialist may inspect once the bridge is understood, but a quotation is not proof the slate has failed. The report has not specified a chemical injection or any other remedy.
What should you ask your surveyor?
- How far above the slate does the new path sit, and is the slate still visible anywhere?
- Are the internal damp marks limited to the wall the path covers?
- Has a leaking rainwater pipe on that same stretch been ruled out, or not?
What are the typical next steps?
- Photograph the path against the slate line while access is still easy.
- Ask the seller who laid the path and whether any damp works were done inside.
- Get a builder to price clearing the slate, not a treatment for unproved rising damp.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a high reading on the plaster settle the cause?
No. A surface reading shows the plaster is damp at that spot. It does not show whether water crossed a bridged slate course, rose through a failed course, or arrived from a leak. This survey has not treated a meter result as a diagnosis of rising damp. The bridge is the finding that can actually be seen.
Should the slate course be replaced before you commit to the house?
Not on this evidence. The survey has recorded a path bridging a slate course, not a failed course. Replacing slate is invasive and may be unnecessary if the path is simply too high. Ask a builder to look at lowering the ground first. The report has not specified a new damp-proof course.