Build-up
Tanking (waterproof membrane on floor and 1.8m+ up walls) — paint-on liquid membrane £30–£55/m². Gradient former (pre-fab tray or cement screed to fall) £400–£900. Linear or central drain £150–£500. Underfloor heating mat £35–£80/m². Tiling labour £55–£120/m² (porcelain) or £85–£180/m² (large-format/natural stone). Glass screen (10mm toughened) £450–£900.
Wet room vs walk-in shower vs tray
Wet room — completely open, no upstand, drain in floor. Walk-in shower (low-profile tray) — flush tray with 25–40mm upstand. Standard tray + enclosure — 50–150mm upstand, traditional. Wet room maximises accessibility (wheelchair access friendly) and feels luxurious but demands flawless tanking; failed tanking = ceiling leak in room below. Tray + enclosure failures are contained.
When wet rooms work / don't
Best: ground-floor over concrete (less risk if tanking fails), small en-suites where standard shower won't fit, accessibility-driven projects, premium master en-suites. Worst: timber suspended upstairs floors without expert tanking, where budget can't stretch to proper drainage and large-format tile.
