Damp and moisture meters
The seller calls the bathroom a wet room. Once the tiles are fixed, what of any tanking can a visual survey still see?
Not the tanking. Once the tiles are fixed, a visual survey cannot see any membrane the seller's wet-room claim depends on. The survey can record the tiles, the gully and the name the seller uses. It cannot see a waterproof layer under sound finishes, and it has not lifted them. Calling the bathroom a wet room does not prove a membrane was used, that it is complete, or that it turns up the walls. Do not take the tile face as a view of the tanking. Ask what papers describe it.
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?
Tanking is the waterproof layer. Tiles and grout sit on top of it. When those finishes are fixed and intact, the layer is covered. A visual survey can note cracks, loose tiles, staining and the waste. Those clues are not the membrane. The seller's name for the room is a claim about how it was built. The inspection cannot confirm that claim through a finished surface, and the absence of a shower tray does not prove the layer either.
Ask, through your solicitor, for any guarantee or drawing that describes the tanking, and read it against what the survey could see. Do not drill the tiles on a viewing. If the report noted staining or a slow waste, follow those points on their own. They still do not show what is under sound tiles. The wet-room label and the hidden layer stay open until someone has papers or opens the finish with permission.
What should you ask your surveyor?
- Which parts of the bathroom finish were intact, so that no tanking edge was visible?
- Did you see any upstand, former or gully detail that was not simply tiled over?
- Was staining present, or was the wet-room point only the seller's description?
What are the typical next steps?
- Do not treat fixed tiles as a view of the tanking.
- Ask the solicitor for any guarantee or drawing that names the waterproofing.
- Do not drill or lift tiles on a viewing.
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
If there is no shower tray, does that prove a tanked wet room?
No. A floor without a tray is a shape. It does not show a membrane under the tiles, and the survey could not see one.
Can a moisture meter on the tiles certify the tanking?
No. A meter on the surface is not a view of the layer underneath. The survey still cannot see tanking through fixed tiles.