How to Plan a Wet Room Installation in 2026 (UK)
A successful wet room comes down to five things: floor structure, waterproofing, drainage falls, building regs and the right fitter. Get the tanking and the falls right and a wet room lasts decades; get them wrong and you get leaks into the room below. A typical UK wet room costs £5,000–£10,000+ in 2026 depending on size, floor build-up and finishes.
Planning a wet room step by step
A wet room is a fully waterproofed (“tanked”) bathroom where the shower area drains directly through the floor, with no tray or enclosure kerb. The planning order below matters — each stage depends on the one before it.
1. Assess the floor structure and drainage feasibility
Concrete floors are the easiest to work with — the drain and falls can be formed directly. Suspended timber floors need a purpose-made sloping shower former (deck) let into the joists, plus reinforcement and often notching that a structural check must approve. Confirm the waste can reach a soil stack at the required fall before anything else — this is the single most common reason a wet room won’t work in a given room.
2. Choose and install a full tanking (waterproofing) system
The waterproof membrane is what makes it a wet room, not the tiles. Use a complete tanking kit — liquid membrane or matting with reinforced tape at every joint, corner and pipe penetration, taken up the walls to at least 1.8m in the shower zone. Skimping here is the number-one cause of failure.
3. Set the drainage falls to the gully
Water has to run to the drain by gravity. Aim for a fall of roughly 1:40 to 1:80 across the shower area to a linear channel or point drain. Pre-formed sloping shower decks build the correct fall in automatically; screeded floors need the fall trowelled in by an experienced fitter.
4. Plan electrics, ventilation and heating to building regs
Electrical work in a bathroom is notifiable under Part P and must respect the IP-rated zones around the shower. Adequate extract ventilation is required under Part F to control moisture. Underfloor heating is popular in wet rooms because it helps the floor dry quickly. Use slip-resistant tiles (R10/R11) for safety.
5. Hire a qualified wet-room fitter and compare three quotes
Wet rooms are unforgiving of poor workmanship. Choose a fitter with specific wet-room and tanking experience, ask to see previous jobs, and compare three quotes on the same written scope including the tanking system and building-regs sign-off.
Typical wet room costs in 2026
A small guest wet room is around £4,500–£6,500; a standard family wet room £6,500–£10,000; and a large or luxury wet room with underfloor heating and premium fittings £10,000–£15,000+. Tanking, drainage and any timber-floor strengthening make up a large share of the difference over a standard bathroom refit.
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