Cost your wet-room fixture replacement.

Replacing fixtures in an existing wet room (shower head, mixer, glass screen, drain, or the trio of toilet/basin/towel rail) typically costs £300–£2,500 in the UK depending on what's being swapped. The big variable is whether the tanking — the waterproof membrane under the tiles — has to be disturbed. If it doesn't, the job is straightforward; if it does, costs jump.

Wet rooms are different from regular bathrooms because the entire floor area is part of the shower zone. That means waterproofing isn't just at the shower tray; it's continuous across the whole floor and a defined height up the walls. Anything that breaks the tanking risks leaks under the tiles.

Typical UK fixture replacement costs

Which jobs need the tanking disturbed?

• Doesn't disturb tanking — shower head, exposed thermostatic mixer, towel rail (if surface-mounted), basin and tap if connections come from behind a panel.
• Risks disturbing tanking — concealed shower valve (built into the wall), drain replacement, toilet pan if soil pipe alignment changes.
• Always disturbs tanking — drain or gully replacement (the floor must be cut), shifting any wall fixture position to a new location.

Replacing a thermostatic shower valve

The most common wet-room fixture replacement, and one where it pays to choose carefully. Concealed valves (built into the wall) are tidier visually but mean any future replacement involves removing tiles. Exposed valves are easier to swap and cheaper to replace later, at the cost of being visible.

For a like-for-like swap (same brand and back-plate footprint), expect £250–£400 fitted. If you're going from one brand to another with a different footprint, the new valve may need to cover a wall hole or require fresh tile work — the bill can rise to £500–£800+.

Drains and gullies — the highest-risk swap

Replacing a wet-room drain or shifting a linear gully means cutting the tiles and the underlying tanking. This is when leaks under the floor get discovered: existing tanking is often older or poorly applied. A good fitter will pull the floor up to the screed, re-tank with a fresh membrane (Schluter, BAL, Mapei systems) and retile. Plan for 3–5 days and £1,500–£3,500 for a partial re-tile around the gully.

Things people often miss

• Matching tiles — if you need to replace tiles around a new fixture, the original batch may no longer be available. Take a sample to a tile specialist before starting; have a backup pattern ready.
• Soil pipe alignment — if you replace a toilet, the new pan must line up with the existing soil pipe. New brands often have different connection heights. A flexible pan connector solves this for £15.
• Heated towel rail BTU output — modern designs trade aesthetics for output. A slim ladder-style rail might output 30% less BTU than a chunkier replacement, leaving the bathroom cooler. Check the spec.
• Electrical zoning — towel rails and lighting in wet rooms must be IP-rated for the zone they're in (typically IP65 for zone 1, IP44 for zone 2). Non-compliant fittings will fail any future EICR or sale survey.

Frequently asked questions

Want a local pro to handle this? A wet-room specialist (a bathroom fitter with tanking experience) is the right call for anything more complex than a shower-head swap. Don't use a general plumber for drain or concealed-valve work — wet-room tanking is a specialist skill.