Wet Room Cost Calculator

Wet room conversions in London start from around £8,000 for a small en-suite and typically run £9,000 to £11,500 for a standard-sized bathroom. That covers strip-out, full tanking using a Schluter or Mapei system, the level-access drainage former, plumbing, Part P electrics, tiling, and fixtures. Underfloor heating adds £1,500 to £2,500. Premium fixtures and large-format porcelain push a larger room towards £15,000 to £17,000. Converting a room that was never a bathroom adds £1,500 to £3,000 for new waste and soil pipework.

Two things: tanking and the floor. A standard bathroom is waterproofed around the shower enclosure; a wet room has to be waterproofed as an entire room, with membrane up the walls and across the whole floor, because there's no tray containing the water. The floor also needs to be built with a gradient falling to the drain, which on a timber-joisted Victorian floor means a preformed sloping former, not just a screed. Do either of those badly and the leak shows up in the ceiling below a year later.

Badly built ones do, and they've earned wet rooms an unfair reputation. The failure is almost always the tanking: membrane not carried high enough up the walls, corners not reinforced, or tiling started before the membrane cured. We use full Schluter or Mapei tanking systems, carry the membrane to ceiling height in the shower zone, and respect the 24-hour curing time even though it adds a day to the programme. That's also why wet rooms take 3 to 4 weeks rather than the 2 to 3 for a standard bathroom.

Small bathrooms are where wet rooms make the most sense. Removing the shower tray and enclosure frees up floor space a 1.7m bathroom layout can't otherwise find, and a glass screen keeps spray off the WC and basin. The one caveat in a small room: everything is in the splash zone, so towel rails and storage need positioning with that in mind. Most of the en-suite wet rooms we build are under 4 square metres.

As a second bathroom or en-suite, yes — an extra washing space reliably helps a London valuation. Replacing your only bathroom with a wet room is the one move to think twice about: some buyers with young children want a bathtub, and removing the only bath narrows your market. Our usual advice is wet room for the en-suite, bath in the family bathroom, which is the combination buyers ask for most.