The waterproofing requirements and the membrane systems that meet them

Behind the tiles sits the layer that actually keeps a bathroom dry: the tätskikt. GVK's requirements for it are the heart of the whole standard — everything else exists to protect this layer or to give it a sound base.

Full coverage, with upstands

The general requirements are strict about where the membrane goes:

• Bath and shower rooms get a membrane on the whole floor and all walls.
• Sloped walls or ceilings near a bath/shower, at risk of water or moisture, are also membraned.
• WC rooms, laundries and technical rooms get a membrane on the whole floor with an upstand onto the wall.
• The floor membrane is always carried up the wall (an upstand), even in wet zone 2, so water can never get behind it at floor level.

Sealed joints, no doubling, right vapour resistance

Where two different membrane types meet, at least one responsible supplier must provide a written mounting instruction for that exact combination. Double membranes are not allowed (and a vapour barrier is not a tätskikt). A membrane under ceramic tiles must have a vapour-passage resistance over one million s/m, unless a formal moisture-safety design applies — so moisture can't build up behind the tiles.

The systems that deliver it

GVK approves several membrane categories, each installed exactly per the supplier's documented method by GVK-authorised fitters:

• Plastic (vinyl) mat — as a combined seal and surface, or as a seal under ceramic.
• Sealing-foil systems — bonded sheet membranes.
• Liquid-applied systems — built up in controlled coats.
• Tight-board systems — approved waterproof boards.

What M5 brings to Dubai

We seal the whole floor and every wall, carry the membrane up the walls, respect the joint and vapour rules, and install one approved system as a complete kit. You never see it — which is exactly why it has to be done right.

Official source: this is M5's plain-language summary, not the official text. For the full rules see GVK — gvk.se.