How Balcony Drainage Slope Actually Works

The conventional way to drain a balcony is to slope the screed toward a drain point. That works, but it means the finished floor is never quite level, and the fall has to be built by hand at pour stage — a detail that's easy to get inconsistent across a large terrace or a multi-unit facade.

WTI's balcony system inverts that: each 1000mm channel section carries a 2mm internal fall, built into the channel body itself. Three channels laid end to end give a continuous 6mm total fall to the outlet, with slope continuity maintained across joints — so the fall accumulates section by section rather than depending on screed work.

The grating itself sits dead flat and flush with the surrounding tile throughout. The floor can be laid level; the channel does the work the screed would otherwise have to do.

A double-slot tile-insert grating keeps the surface reading as continuous tile rather than a visible drain line — the system is built in SS304 as standard, or SS316L, at a 150mm channel width. For a specifier, the practical upside is that the internal slope removes one of the more error-prone details in balcony waterproofing from the screed trade's hands and puts it into a manufactured, repeatable channel section instead.