UK trade guideToilet & Cistern 7 min readUpdated 9 July 2026

How to Fit a Back-to-Wall Toilet (UK)

Install a back-to-wall WC pan onto a concealed cistern frame. Alignment, waste connection and bolt-through.

GeberitRocaGroheTECE

Frame first

Frame must be fixed to structural wall or floor — never plasterboard alone. M12 threaded rods project through the plasterboard to accept the pan. Level and plumb crucial.

Waste and inlet

4" pan connector with 90° or 45° elbow depending on frame outlet position. Flush pipe from cistern to pan — must be correct length for the specific frame.

Frequently asked questions

What height should the pan rim sit?
400 mm above finished floor for standard use, 450 mm for accessible.
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