Norwegian Wet-Room Falls & Waterproofing (TEK17)

The requirement

TEK17 §13-15 requires a drain, falls that carry water to it, visible leak water and a watertight layer that protects the structure. DiBK’s free guidance does give numbers. They are pre-accepted solutions, not a full wet-room design.

Floor falls and edges

For the shower zone, the guidance gives three choices:

• At least 1:50 within 0.8 m of the drain. If the shower is offset, extend that fall from its spray area to the drain.
• At least 1:100 in a shower area recessed at least 10 mm. Check step-free shower requirements too.
• At least 1:100 across the whole floor.

Leak-water control is a separate check. Its alternatives are a whole-floor 1:100 fall, or a watertight edge 25 mm above the finished floor, reduced to 15 mm at a doorway. There must be no reverse fall from a place where leaks can occur.

The waterproof layer has its own edge datum: at least 25 mm above the drain grate. Do not confuse that with height above the finished floor. Check Figure 1 for the wet zone, plus drain joints and pipe seals.

Before installation

Choose one complete approved detail for the job. Check the substrate, membrane, drain and door together. Keep the product instructions and the site checks with the drawings.

Sources

• DiBK TEK17 §13-15, guidance to (2)(b)–(d) and Figure 1.
• Norwegian building-code hub.

Source checked on 6 September 2026. This is a source-based summary, not a professional design approval.