Wet Room Installation in South London

What Affects the Cost?

• •Floor build-up needed for the gradient and falls to the drain (solid concrete vs suspended timber joists)
• •Tanking system specified and how far up the walls the membrane is carried
• •Drainage type and run to the existing soil stack
• •Underfloor heating included or left out
• •Tile size and material (large-format porcelain needs a flatter substrate)
• •Whether the room is a fresh build or a strip-out of a failed previous conversion

Areas We Cover

Frequently Asked Questions

How long does a wet room last before it leaks?

A wet room that has been tanked properly will run for the life of the bathroom without leaking. The ones that fail leak within a year or two, and they leak for the same reason almost every time: the tanking was skimped. Water in an open shower does not just hit the floor, it runs down the walls, sits in the corners and finds any gap in the waterproofing. So the membrane has to be a continuous layer, bonded at every joint, carried up the walls and lapped into the floor with no break. We use Schluter or Mapei systems, dress the membrane into the internal corners and around the drain, and let it cure before a single tile goes on. Tile and grout are not waterproof. The tanking underneath is. Get that layer right and the room outlasts the tiles.

Is a wet room a good idea for a small en-suite?

Yes, and a small en-suite is often the best room in the house for one. A wet room under 4 square metres reads larger because there is no shower tray, no enclosure and no step, just one open floor that drains away. That removes the visual clutter that makes a tight en-suite feel like a cupboard. The whole floor falls gently to the drain, so you lose no usable space to a tray, and a single sheet of glass is usually all the screening a small room needs to keep splash off the WC and basin. The catch with a small room is that the fall still has to work across a short distance, so the gradient is set carefully and the drain placed where the water naturally runs. On a tight floor that planning matters more, not less.

Can I have a wet room on a timber floor upstairs?

Yes. Most of the wet rooms we fit in South London go into upstairs en-suites on suspended timber floors, not ground-floor concrete. A timber floor flexes, and a flexing floor cracks rigid tanking and grout, so the build-up is the part that decides whether it lasts. We over-board the joists with a tile backer board fixed at proper centres to stiffen the deck, set the gradient into that build-up, then carry the tanking membrane across the floor and up the walls as one bonded layer. A recessed former or graded boards create the fall to the drain without dropping the finished floor below the doorway. Done this way a timber floor takes a wet room without movement showing through. The waste run has to fit between the joists, which we check at the site visit, because that one detail sets where the drain can go.

Do wet rooms need building regulations or planning permission?

Converting a bathroom or en-suite into a wet room does not need planning permission, because it is internal work that does not change the look of the house. Building regulations do apply to parts of it. Any new or altered electrics in the room, including underfloor heating, fall under Part P and have to be installed and certified to that standard. Drainage and ventilation are covered too: the room needs adequate extraction, and the waste has to discharge correctly to the existing soil stack. If we move the drain or add electric underfloor heating, that work is done to the regulations and certified. The tanking itself sits under good-practice standards rather than a regulation, but it is the part we treat as non-negotiable. We sort the notifiable parts as part of the job so you are left with the certificates, not the paperwork.

What goes wrong with a DIY or cheap wet room conversion?

Two things, almost always. The first is the fall. The floor has to slope to the drain across the whole wet area, and getting an even gradient into a build-up is fiddly, so a botched job ends up with water pooling away from the drain or sitting against a wall. The second, and worse, is the tanking. People tile over a painted-on waterproofer that was never lapped into the corners or taken high enough up the wall, and water tracks behind it into the floor and the room next door. By the time it shows as a stain on a ceiling below, the floor is already soaked. When we strip out a failed conversion it is nearly always one of those two faults. We set the fall before tiling and tank floor and walls as one continuous, cured membrane, which is the slow part most cheap jobs rush.

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