Wet Room Installation in London: Cost Guide and What to Expect
A complete cost guide to wet room installation in London covering tanking, drainage, gradient screed, anti-slip tiling, the additional requirements for flats above other dwellings, and typical project timelines.
Wet Room Installation in London: Overview
A wet room is a fully waterproofed shower area at floor level, with no tray, no step, and no threshold. The entire shower zone -- and often the entire bathroom floor -- drains to a floor-level drain through a gentle gradient in the floor surface. The visual result is a clean, contemporary, level-access shower that has become one of the most sought-after finishes in London bathroom renovations. The installation is more involved and more expensive than a standard shower tray, but the result is qualitatively different and, where done correctly, highly durable.
Wet Room vs Shower Tray: The Core Difference
A shower tray is a pre-formed waterproof basin that sits on the floor -- the tray itself is the primary waterproofing element, and the installation is relatively forgiving because the tray prevents water reaching the floor structure. A wet room transfers the waterproofing responsibility to the floor structure itself, which must be fully tanked before tiling. If the tanking system fails, water reaches the substrate and eventually the structure -- in a London flat above another dwelling, this means water reaching the ceiling of the flat below. The tanking specification for a wet room in a London flat must be treated seriously.
Tanking: The Critical Element
Tanking is the application of a waterproofing membrane to the entire wet room floor area and to the lower sections of all walls. The membrane is typically a cementitious slurry applied in two or three coats, or a proprietary sheet membrane bonded to the substrate with a primer and reinforced at junctions with jointing tape. The membrane must be continuous -- any gap or pinhole in the coverage will eventually allow water to penetrate. Junctions between the floor and walls, around the drain flange, and at any penetrations through the floor must be reinforced with jointing tape and primer. The membrane is typically taken at least 150 mm up all walls and 100 mm behind the drain body before the drain flange is fitted on top.
For London flats above another occupied flat, a sheet membrane system (rather than a slurry-only approach) provides the most reliable waterproofing. A sheet membrane has a defined minimum thickness and documented performance data, which is important if a claim is ever made about a leak.
Floor Former and Gradient
The floor of a wet room must drain towards the drain at a gradient of approximately 1 in 80. In new build properties with a concrete structural floor, this gradient is typically achieved by a screeded bed. In London flats with a suspended timber floor, a purpose-made floor former -- a pre-formed foam or cement board insert shaped to the required gradient -- is placed on top of the joists and the tiles are laid on top of the former. The former also provides a waterproof substrate when tanked. The drain is fitted through the floor former and connected to the waste below the floor.
In properties with suspended timber floors, the drain position must be planned to avoid cutting through structural floor joists. Where the drain must be positioned over a joist, the waste routing below may need to run between joists to reach the stack or existing waste pipe.
Anti-Slip Tile Requirement
Wet room floors must be tiled with anti-slip rated tiles. The Tile Association and BS 8300 recommend a minimum R10 slip resistance rating for wet barefoot surfaces. Smooth polished porcelain tiles, however attractive on walls, are not suitable for wet room floors without surface texture or profiling. Small-format mosaic tiles provide inherently good slip resistance due to the volume of grout lines but require very high grout maintenance in London hard water conditions. A textured large-format tile in the R10 to R11 range balances aesthetics, safety, and maintenance.
Drainage Options
Linear channel drains running along one wall of the wet room are popular in contemporary London bathrooms -- the floor gradient drains toward one edge rather than a central point, which simplifies the tile layout and avoids complex multi-direction falls. Central floor drains are more traditional and suit square rooms. Both options are available in stainless steel, brushed brass, and matte black finishes to coordinate with the shower valve and fittings.
Project Timeline and Cost
A wet room installation in a standard London bathroom (approximately four to five square metres) takes two to four days from strip-out to final grouting and sealant. The timeline breaks down as: strip-out and substrate preparation on day one; floor former installation and tanking on day two; wall tile installation on day three; floor tile installation and grouting on day four, with final sealant applied once the grout has cured (typically 24 to 48 hours).
Cost breakdown for a standard London wet room: floor former and tanking system £300 to £600 materials; drain £80 to £250 depending on style; tiling labour £600 to £1,200 for floor and wet area walls; tiles £15 to £50 per square metre plus 15 percent waste allowance; shower valve and head £200 to £600; plumber to connect shower valve and waste £200 to £400; total project range £2,000 to £5,000 for a standard bathroom footprint, excluding any partition wall or structural work.