Do bathroom walls need to be straight before tiling in Glasgow?

Walls do not need to be mathematically perfect, but they need to be sound, suitably flat and prepared well enough for the tile size and layout being used. Large-format tiles in particular can make uneven walls much more obvious and can be harder to install well on a poor substrate.

In older Glasgow flats, layers of previous finishes, damaged plaster or out-of-plumb walls can become apparent during strip-out. Preparation may involve repairs, boarding or other corrective work before waterproofing and tiling.

Doherty's Glasgow bathroom fit-out process treats wall preparation as part of the build rather than assuming new tiles can simply be fixed over whatever is there. That is one reason a complete renovation should be surveyed before a final price is agreed.