UK trade guideBathroom Spares 4 min readUpdated 9 July 2026

How to Fit a Shower Tray Waste (UK)

Install a 90 mm high-flow shower waste in a stone resin, acrylic or steel tray. 50 mm water seal compliance.

McAlpineVadoWirquin

Flow rate matching

Standard 90 mm waste = 22 L/min. Rainfall showers >25 L/min need a fast-flow trap (McAlpine STW10).

Fit

Silicone the flange to the tray top. Rubber gasket below. Backnut with tray in position. 50 mm minimum trap seal for Building Regs H1.

Frequently asked questions

Can I fit a shallow trap in a wet-room?
Yes — McAlpine STW6 sits at 60 mm total depth for wet-room installs.
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