Fastening sanitaryware and sealing fixings in wet zones

A fixing in a wet wall or floor is a hole through the waterproofing waiting to happen. Säker Vatten sets out how sanitaryware, mixers, shower walls, grab handles and pipe clamps are fastened and sealed so they never become leak paths.

How fixings are made

Screw fastenings are made into concrete or other solid structure, wooden studs, wooden noggings, or a board construction tested and approved for the purpose. Where the wall is board on studs and not an approved system, it must be reinforced — typically with noggings. Fastening with adhesive is allowed using the HVP product supplier's approved materials and method.

Floor and wall fixing specifics

For floor fixings the mounting surface must be free of underfloor heating and allow a drill and screw depth of 60 mm; pipes and electrical wiring may run beneath only if they are more than 60 mm deep. A lavatory or bidet needs a flat, rectangular mounting surface of at least 300 x 400 mm, with the floor beneath sloping no more than 10 mm per metre, so the fixture stands steady. Wall-mounted fixtures may require wall reinforcement or a special fixture bracket.

Seal every fixing

Critically, all fastenings are sealed to the wall or floor waterproofing. The sealing material must be fixed to the surface and be water-resistant, mould-resistant and age-resistant. This is the rule that turns a screw hole from a future leak into a closed detail.

Official source: this is M5's plain-language summary, not the official text. For the full rules see Säker Vatten (sakervatten.se).