Substrate and floor gradient: getting the base under the tile right

A beautiful tiled floor over a poor base is a failure with a nice finish. BBV is exacting about the substrate and the fall, because both are set before a single tile is laid and neither can be fixed afterwards.

A substrate the membrane and tile can trust

Substrates must be able to sustain weight, be dry, cleaned and free from loose particles. Cavities and uneven surfaces are filled or sanded before waterproofing; filler residues, paint splashes and pure lime plaster are removed. Wall and floor surfaces must have documented or proven suitability as a base for the membrane and tiling — if they don't, the substrate is replaced or supplemented with suitable material. Concrete and wooden-joist floors carry special requirements combining thermal behaviour, load-bearing capacity and watertightness. The substrate is inspected before work begins, and the requirements apply to concrete, lightweight concrete, plaster, filler and screed, and boards alike.

Floor gradient — the exact fall

The floor must slope to the drain in both the substrate and the finished surface, with no negative slope (backfall) anywhere:

• In the space for bathtub or shower next to the drain, the fall is 1:150 to 1:35 (7–30 mm/m) — with a recommended 15 mm/m.
• Areas not normally walked on (for example between the drain and the nearest wall) may be up to 1:25 (40 mm/m).
• Other floor areas should fall 5–10 mm/m.

Too little and water pools; too much and tiles are hard to lay flat and the floor feels wrong underfoot.

What M5 brings to Dubai

We prove the substrate is sound and dry, correct it where it isn't, and build the fall into both the base and the finished floor within these tolerances. It's the invisible groundwork that decides whether your tiling lasts or lifts.

Official source: this is M5's plain-language summary, not the official text. For the full rules see Byggkeramikrådet (BKR) — bkr.se.