Building Regulations
Moisture safety: what the building code actually requires
BBR's moisture rules are the legal reason wet rooms are built the way they are. Watertight layers where water lands, floors that drain, and the trade rules that exist to meet the law.
Why this matters to you
The law behind a dry home — and the reason every trade in your bathroom follows the same rules.
- Watertight layers required exactly where water lands
- Floors must drain, with no backfall — by law
- The standard the waterproofing, tiling and plumbing rules exist to meet
Every rule about membranes, falls and sealed penetrations traces back to one place: Boverket's building regulations (BBR) require that a building be safe from moisture. The trade standards are just the accepted way to meet that legal duty.
The legal requirement
Under BBR, buildings must be designed and built so that moisture cannot cause damage or harmful microbial growth. Boverket specifically designates the areas that need a waterproof or water-repellent layer (section 6:533): the wettest surfaces require a watertight layer, and others a water-repellent one. And floors regularly exposed to liquid water must have a drain and a fall towards it, with no backfall in any part of the room (the current requirement in BFS 2024:8, chapter 7, §11).
Performance, not a fixed recipe
BBR sets the *performance* a wet room must achieve, not a single method. That's deliberate — it leaves room for different technical solutions, as long as the result is demonstrably dry and durable.
How the trade rules fit
The industry rules — Säker Vatten for plumbing, GVK for waterproofing, BKR/BBV for tiling and MVK for painted surfaces — are recognised as the professional way to meet BBR's moisture requirement. Building to them, and documenting it, is how a contractor demonstrates the law was met rather than merely claimed.
Moisture-safety design
For higher-risk situations, BBR relies on moisture-safety design (fuktsäkerhetsprojektering) — the building owner's systematic process, during design, to ensure the finished building won't suffer moisture damage. It's the planning discipline behind a wet room that lasts.
What M5 brings to Dubai
We build to the trade rules precisely because they satisfy BBR's moisture requirement, and we design moisture safety in from the drawings. The result is a bathroom that meets a real legal standard for staying dry — the same standard used across Sweden.
Official source: this is M5's plain-language summary, not the official text. For the full regulations see Boverket — boverket.se.
Want this standard on your project?
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