Wet Room Installation in London

Falls, tanking and floor build-up

A wet room removes the tray and the step, so the floor itself has to carry water to the drain. That makes three things critical: the fall, the waterproofing beneath the finish, and whether the floor construction can accommodate the build-up at all. In London the third is usually the one that decides whether a wet room is viable.

Fall is formed, not assumed. Either a pre-formed sloping former is set into the floor, or the screed is laid to fall towards a linear or centre drain. Too little fall leaves standing water; too much is uncomfortable underfoot and shows in the tile lines. On a timber floor the former normally sits between joists, so joist direction and spacing are checked before the drain position is fixed.

Tanking is what actually keeps water out of the building. A liquid or sheet membrane is taken across the floor and up the walls of the wet zone, dressed into the drain flange and sealed at internal corners and pipe penetrations with matching tape and collars. Tiling is a finish, not a waterproof layer, and treating it as one is the most common cause of failure.

In upper-floor flats and conversions this matters more than anywhere else, because a failure has someone else's ceiling beneath it. The membrane detail, the standard of the seal at the perimeter, and how pipe penetrations are formed carry more weight in that situation than the appearance of the finish does, and most leases will require the work to be done to a standard that reflects it.

Level access is often the reason for a wet room in the first place. Removing the step suits anyone who needs step-free showering, and it also removes the junction where trays most commonly fail. Where the floor depth simply is not available, a low-profile tray in a level-access arrangement achieves much of the same result without cutting into the structure.

Common questions

Can a wet room be installed in an upper-floor flat?

Yes, and the waterproofing standard matters more there than anywhere else, because a failure affects the property below. A former is usually set between the joists to create the fall, the floor is stiffened where required, and the membrane is dressed into the drain flange and up the walls. Most leases will also require freeholder consent before the work starts.

How much floor depth does a wet room need?

Enough to form the fall and accommodate the drain body and trap beneath it. On a solid floor that usually means cutting in; on a timber floor the depth available between joists governs. Where the depth is not there, a low-profile tray in a level-access layout achieves most of the same result.

Does a wet room need a screen?

Not structurally, but usually in practice. Without one, spray travels further than people expect and the whole room stays wet for longer after use. A single fixed panel is often enough to control that while keeping the open, step-free layout the wet room was chosen for.