Retiling is tiling plus demolition plus repair, and the third part is the one that makes quotes unreliable.
The build-up
Start with the tiling itself. MyJobQuote gives £600 to £800 in labour for a medium bathroom fully tiled, or £500 to £800 as the typical overall range, with materials on top.
Add tile removal at around £30 an hour. A full bathroom strip is not a quick job, particularly where the tiles are well bonded, and the labour on removal alone can run to several hundred pounds.
Then add making good, and this is where the number becomes uncertain.
Why stripping reveals problems
Tiles come off in one of two ways. Either they release cleanly, which happens when they were poorly bonded in the first place, or they hold firm and bring the surface behind with them.
The second is more common on a properly tiled wall, and it means the plaster or plasterboard behind is damaged. In a modern bathroom that usually means patching or reboarding. In a Victorian or Edwardian property, where the tiles may be on original lime plaster, it frequently means the wall needs replastering or boarding out entirely before it can be tiled again.
That is a plasterer's visit, materials, and then drying time before the tiler can start. It can add a week to the schedule and several hundred pounds to the cost.
The things stripping exposes
Once the tiles are off, you can see the substrate properly, and bathrooms hide problems.
Water damage behind a shower is common, especially where the original tiling was never tanked. Damp, soft plasterboard, corroded fixings and in the worst cases rotten timber all show up at this point. None of it can be tiled over.
This is genuinely a good thing, in the sense that finding it now is far better than finding it in five years. But it does mean a retiling budget should carry a contingency that a new-build tiling budget does not.
Getting a quote that survives contact
Ask the tiler to price the job in stages: removal, making good as a provisional sum, preparation and tanking, then tiling.
Ask what happens if the wall needs replastering, and agree the rate before work starts. A stripped bathroom is a poor negotiating position.
Allow fifteen to twenty per cent contingency on the whole job. On a property over a century old, allow more.
The alternative: tiling over
Tiling over the existing tiles avoids all of this, and where the old tiles are sound, flat and well bonded it is a legitimate approach.
Tap every tile first. Any that sound hollow must come off, and if a significant number do, tiling over is not an option.
The constraints are weight, since two layers of tile may exceed what a plasterboard wall should carry, and height on floors, where an extra 15mm to 20mm affects doors and thresholds.
When retiling is not the answer
If the tiles are sound and only the grout looks tired, regrouting is a fraction of the cost and transforms the appearance. Discoloured grout makes a perfectly good bathroom look worn out, and people replace tiles that did not need replacing.
Look at the tiles themselves rather than the overall impression before committing to a strip.