A wet room is one of the most rewarding projects you can take on in a UK home. It turns even a modest bathroom into something that feels considered and calm, and it makes brilliant use of an awkward or compact space. It also throws water at every surface, every day, so the decisions that matter most tend to be the ones you never see once the job is finished. Tiles are the part everyone wants to talk about — understandably, since you will look at them for the next twenty years — but they sit on top of a system. Get the system right and almost any sensible tile will serve you well.

Start With the Substrate, Not the Tile

Before you fall in love with a finish, settle the tanking. A wet room is not a bathroom with a shower tray; it is a room that is designed to get wet, and the waterproofing has to be continuous across the floor and up the walls. In practice that means a properly specified tanking system, either a liquid-applied membrane or a flexible matting, carried across the whole floor rather than just the shower zone.

The details that fail are always the same ones:

• Internal corners and wall-to-floor junctions, which need reinforcing tape bedded into the membrane rather than a smear of sealant.
• Pipe penetrations and waste outlets, which need collars and careful sealing.
• The edge of the wet zone, which should extend at least 150mm beyond the shower area and up to full shower height on the walls.
• Any movement between substrates — timber and screed meet, for example — which needs a decoupling membrane or a movement joint.

British Standard guidance for tiling in wet areas is worth reading before you brief anyone, even if you are doing the work yourself. It costs an evening and saves a fortune.

Falls: The Detail That Decides Whether It Works

Water has to leave the room, and it will only do that if the floor is shaped to encourage it. Falls for a wet room generally sit somewhere between 1:80 and 1:40, depending on where the drain is. A linear channel set against the wall can work with a gentler fall across a single plane; a centre or off-centre waste usually wants something closer to 1:40, falling from all sides.

You have two routes. A pre-formed shower tray former is quicker, gives you a guaranteed fall and suits a linear drain neatly. A screeded floor gives you freedom of shape and size but depends entirely on the skill of whoever lays it. Whichever you choose, test it before tiling: flood the floor with water, watch where it pools, and leave it for a day. If water sits anywhere, it will sit there forever once the tiles are down.

Understanding Slip Ratings

This is where most of the anxiety lives, and it is simpler than it looks. Barefoot wet areas are usually classified under the A, B, C system, where A is the least textured and C the most. Shod areas use the R scale, where R10 is a common domestic standard, R11 is a sensible choice for a wet room floor, and R12 and above become noticeably rougher underfoot.

Two caveats matter. First, texture and cleanability pull against each other — a deeply profiled tile that grips beautifully also traps shampoo and limescale, which is a particular consideration on hard water. Second, joints and grout lines contribute real grip. A floor laid in small mosaics with plenty of grout lines will generally feel safer underfoot than the same rating in a large format tile. If you want large tiles on the floor, go one step up the slip rating to compensate.

Porcelain, Mosaics and Natural Stone

Porcelain is the default for good reason. It is dense, absorbs almost no water, and vitrified porcelain with a matt or lightly textured surface copes well with a wet room. Rectified porcelain gives you tight, even joints. It is also the easiest finish to keep clean.

Mosaic sheets — often 25mm to 50mm tesserae on a mesh backing — are the traditional choice for wet room floors because they follow the falls without fighting them. They also drain quickly and offer excellent grip. Choose a porcelain or glazed mosaic rather than a natural stone one if you want low maintenance.

Natural materials are where a wet room can feel genuinely special. Honed travertine, slate and limestone all work, and sandstone and riven slate bring texture that no porcelain quite matches. But stone is porous: it needs sealing on installation and re-sealing every year or two, and some stones are slippery when wet even when honed. If you are drawn to natural stone, use it on the walls and a matching or complementary porcelain on the floor.

Grout, Adhesive and the Details People Regret

Use a flexible, cementitious adhesive rated to BS EN 12004, Class S1 or S2 — powder-based, mixed on site, never a ready-mixed tub. For grout, epoxy is the hard-wearing choice in a wet room: it resists staining, mould and water ingress, though it is more demanding to apply and to clean off.

• Keep floor joints at 2–3mm and wall joints similar; wide joints in a wet room collect dirt.
• Never grout internal corners or the wall-to-floor junction. Those need a flexible silicone or a suitable sealant.
• Leave the installation to cure fully before grouting and sealing, and keep the room well ventilated afterwards.

Small Choices That Make a Big Difference

Insulation boards under the floor keep the tile warmer to the touch and reduce heat loss. A low-profile electric underfloor heating mat does more than comfort: it helps the floor dry after every shower, which is the single best defence against mould and limescale. A recessed niche built into the tanked wall looks far cleaner than a hanging caddy and costs very little at the right stage. Make sure the drain is accessible for cleaning, and keep a box of spare tiles in the loft. Twenty years from now, you will be very glad you did.