Wet Room Cost by Size and Specification
Prices below are fully installed including tanking, screeded floor, drainage channel, tiling and standard fixtures. They exclude underfloor heating and bespoke joinery.
| Scenario | Floor Area | Spec Level | Estimated Cost |
|---|---|---|---|
| Small en-suite conversion | 2-3 m² | Budget (ceramic tiles, basic fittings) | £4,000-£6,000 |
| Standard bathroom conversion | 4-5 m² | Mid (porcelain tiles, thermostatic valve) | £6,500-£9,000 |
| Large family bathroom | 6-8 m² | Mid-high (large-format tiles, linear drain) | £8,500-£12,000 |
| Designer/luxury wet room | Any | Premium (natural stone, brassware, UFH) | £12,000-£18,000+ |
| New build wet room (no conversion) | 4-5 m² | Mid | £5,000-£7,500 |
| Disabled/accessible adaptation | 4-6 m² | Functional (non-slip tiles, grab rails) | £5,500-£9,000 |
Prices are indicative 2026 UK averages. London/South East typically 20-30% higher.
What Affects the Cost of a Wet Room?
Several factors push the final bill up or down significantly:
- Tanking and waterproofing: A proper tanking membrane is non-negotiable. Budget systems use liquid membrane; higher-spec installs use cement-board backer plus sheet membrane — expect £500-£1,500 just for materials and labour.
- Drainage and gradient: A linear drain or centre-point drain requires a skilled screeder to achieve the correct fall across the whole floor. Screed and drainage installation typically costs £600-£1,200.
- Tiling: Large-format porcelain costs more per m² than standard ceramic. Non-slip rated tiles are essential and may carry a premium. Budget £40-£120/m² for tiles plus £30-£60/m² for fitting.
- Shower fixtures: A basic electric shower costs £150-£300 fitted; a thermostatic valve with multiple outlets costs £400-£1,200 fitted.
- Underfloor heating: Electric mat systems under tiles add £300-£700 for a small room. See our underfloor heating cost guide.
- Structural work: Floors may need reinforcing to bear a screeded wet room, especially in timber-joist houses — allow £500-£1,500 if required.
- London/South East location: Labour rates are 20-30% higher than the national average.
- Existing layout changes: Moving soil pipes or extending plumbing routes adds £300-£800 to the bill.
Wet Room vs Standard Bathroom: Is It Worth It?
A wet room generally costs 30-60% more than a like-for-like standard bathroom refurbishment, which typically runs £3,500-£7,000. The premium buys you a more accessible, easier-to-clean space with a high-end feel — factors that estate agents consistently link to added resale value, particularly in family homes and properties targeting downsizers.
The critical difference is the tanking: every surface the water can reach must be fully waterproofed to prevent long-term damp ingress. Cutting corners here is the single biggest mistake homeowners make — a failed tanking job can cost thousands to put right. Always use a contractor who follows BS 8000-11 and provides a written guarantee on the waterproofing.
Wet rooms are particularly valuable where accessibility is a priority — level access eliminates the step into a shower tray, making them suitable for wheelchair users and older residents. Disabled Facilities Grants (administered by your local council) may cover some or all of the cost for eligible adaptations.
Pitfall: Skimping on Tanking
The biggest wet room failure is inadequate waterproofing. Some fitters apply a single coat of liquid membrane — too thin and too easily compromised at joints. Insist on a full tanking system with cement-board substrate, lapped membrane at all junctions and a minimum two-coat application. Ask for a signed, insured guarantee covering at least 10 years. Remedial damp work after a failed wet room can cost more than the original installation.
Plan Your Budget Before You Buy
Our planner helps you set a realistic refurbishment reserve before you buy — so you know exactly what a wet room conversion will add to your total spend, alongside any other works the property needs.
How a Wet Room Is Installed: Key Stages
Understanding the process helps you verify your contractor is doing the job properly.
Strip-out and preparation
Existing bathroom fittings, tiles and floor coverings are removed. The subfloor and walls are inspected for any existing damp or structural issues before work begins.
Structural reinforcement (if needed)
Timber joists may be strengthened or a plywood deck laid to carry the weight of the screed and tiles without flex, which would crack grout and eventually the tanking.
Drainage installation
The drain and waste pipe are set at the correct level and falls. A centre drain is simpler; a linear wall drain requires more precise positioning.
Tanking
Cement-board or moisture-resistant plasterboard is fixed to walls. A tanking membrane is applied to all walls and the floor, with special attention to internal corners and pipe penetrations.
Screeding
A sand-and-cement screed is laid and floated to achieve the correct gradient (typically 1:80 to 1:60) towards the drain. This is allowed to cure for at least 3-4 days.
Tiling and grouting
Wall and floor tiles are fixed, grouted with a waterproof grout and then silicone-sealed at all changes of plane. Non-slip floor tiles (minimum R10 rating) are required.
Fixtures and finishing
Shower valves, glass screens (if used), towel rails, basin and toilet are fitted. Mains water is reconnected and the installation tested before sign-off.