What affects the cost
Cost depends on whether pipework and electrics need moving (not just swapping fixtures in place), the tiling area, fixture quality, and whether structural changes are needed (like removing a bath for a walk-in shower). Moving a toilet's position, in particular, is one of the more expensive changes because of the soil pipe work involved.
Bathroom lighting and IP ratings
Lighting near water (over a shower, close to a bath) needs to meet a minimum IP (ingress protection) rating for that specific zone — not every light fitting is suitable everywhere in a bathroom. This is part of what a registered electrician checks as part of the notifiable electrical work.
KBSA and TrustMark, what they actually mean
The KBSA (Kitchen Bathroom Bedroom Specialists Association) is the main UK trade body for the sector, though membership is limited to a few hundred companies nationally, so it's not something every bathroom fitter will have. TrustMark is a broader government-endorsed scheme covering many trades — worth asking which, if either, your fitter holds, rather than assuming either is universal.
Three steps to hiring the right bathroom fitter
First, ask to see photos of similar completed jobs, ideally local ones. Second, clarify exactly who does the electrical and plumbing work — the fitter directly, or a subcontracted registered tradesperson. Third, get a written quote that separates labour, fixtures and tiling.
Underfloor heating in bathrooms
Electric underfloor heating mats are a common bathroom addition since they don't need the full manifold a water-based system does, and work well under tile. They need to be planned before tiling starts and are usually a straightforward add during a full refit rather than a standalone retrofit.
Grout and sealant maintenance
Grout and silicone sealant are usually the first things to fail in a bathroom, well before the tiles or suite themselves — re-sealing around a bath or shower every couple of years, and re-grouting where needed, extends the life of the whole installation for relatively little cost.
First fix and second fix in a bathroom refit
"First fix" is pipework and electrical cabling before tiling; "second fix" is fitting the suite, taps and electrics once tiling is done. Getting this sequence right matters — pipework needs to be pressure-tested and electrics first-fixed before the room is tiled over.
Making the most of a small bathroom
A corner shower, wall-hung suite, and a mirrored cabinet instead of a separate cabinet and mirror are common ways fitters maximise a small bathroom without a full structural change. Layout planning matters more in a small space, where a few centimetres can determine whether a design actually works.