Wet Room Fixture Replacement Costs

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

Can I just swap the shower head without involving a plumber?

Yes, in most cases — handheld shower heads connect via a standard 1/2-inch BSP thread to a flexible hose, and the hose connects to the valve outlet. Turn off the supply, unscrew, replace, retape with PTFE. Wall-mounted fixed heads on a rigid arm are slightly more involved but still DIY-friendly.

Will replacing a fixture damage the wet-room tanking?

Only if the job involves cutting through the tile and tanking layer. Surface-mounted swaps (exposed valves, towel rails on existing brackets, taps) don't disturb tanking. Concealed valve replacement, drain replacement and toilet repositioning all do.

How long does a wet-room drain or linear gully last?

The mechanical part (cover, trap) is essentially unlimited if cleaned regularly. The waterproof tanking around it has a similar lifetime to the room — 15–25 years with no movement. Most wet-room leaks come from cracked tile grout, not the gully itself.

Do I need a tiler as well as a plumber for fixture changes?

For most simple swaps, no — your plumber can handle it. For drain replacement, concealed valve swaps to a different footprint, or any work that breaks tile, you'll need a tiler too (or a fitter who covers both trades).

Why is wet-room work more expensive than a regular bathroom?

Two reasons: the waterproof tanking layer adds material and labour cost (£40–£90/m² on top of tiling), and the consequences of getting it wrong are much more expensive. A leak under wet-room tiles can ruin the floor structure below within months.

Can I change the layout of fixtures in an existing wet room?

Yes, but it's substantially more work than a like-for-like swap because soil and supply runs need rerouting and the tanking has to be re-done in any disturbed area. Budget £3,000–£8,000 depending on how radical the changes are.

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.