Wet room drainage explained
In a wet room the floor is the shower, so the drain isn’t a detail — it’s the piece that decides how the floor is graded, which tiles you can lay, and how the finished room looks. There are two families of wet room drain: a point drain (a single central gully the floor falls toward from every side) and a linear drain (a long channel the floor falls toward in one direction). Both keep a properly built wet room bone dry — the choice is about tile size, room shape and the look you’re after. We fit both across Plymouth, Plympton and Plymstock, and we’ll tell you plainly which suits your room before we quote.
Why the drain is the first decision, not the last
People tend to think about the drain near the end — a bit of stainless steel that goes in once the tiling’s done. In reality it’s one of the earliest calls we make on a wet room installation, because the drain type dictates how the floor is graded. The floor has to slope gently toward the drain so water runs away on its own, and the number of directions that slope has to travel is set entirely by where the drain sits.
Get it right and you barely notice the fall while water disappears the moment it lands. Get it wrong and you end up with puddles that sit until they evaporate. So before any tile is chosen, we settle the drain — it’s the hinge the floor turns on.
Point drain, in one line
A single square or round gully. The floor tilts toward it from all four sides, like a shallow funnel. Because the slope changes direction around the gully, you need tiles small enough to follow those planes — smaller formats and mosaics.
Linear drain, in one line
A long, slim channel — a slot — usually set against a wall or across the shower entry. The floor only has to fall in one direction toward it, so large-format tiles lie flat and clean. Sleeker to look at, and the option most Plymouth customers ask for.
Point (centre) drains — the dependable classic
A point drain is the traditional wet room gully: one outlet, roughly central to the shower zone, with the floor falling toward it from four sides. It’s the more economical of the two, and there’s nothing wrong with a well-set point drain — plenty of our neatest wet rooms use one.
Where a point drain shines
- Smaller-format tiles and mosaics. Because the floor slopes in several directions around the gully, you want tiles that bend around those planes. Mosaics are ideal — the many grout lines flex with the falls and add grip underfoot at the same time.
- Square-ish shower zones. When the wet area is roughly square, a central gully falls evenly from all sides and looks balanced.
- Tighter budgets. The gully is cheaper than a channel and the fall is straightforward to form, so it’s the cost-effective route into a wet room.
The one honest trade-off: a point drain and large-format tiles don’t mix. You can’t slope a big rigid tile in four directions at once, so if your heart is set on big porcelain, a linear drain is the better answer.
Where a point drain gets fiddly
- Long, thin shower zones — the four-way fall looks awkward and the far corners drain slowly.
- A large-format tile scheme, for the reason above.
- Rooms where you want the drain tucked to one edge rather than sitting in the middle of the floor.
None of these are dealbreakers — they’re simply the moments where we’d steer you toward a channel. It’s a call we make at survey, alongside the floor former and gradient that carries the fall.
Linear (channel) drains — the modern favourite
A linear drain is a long, narrow channel — often 600mm to 1200mm — set against a wall, across the shower entry or between two zones. Its trick is simple but powerful: the floor only has to fall in one direction to reach it. A single-plane slope is exactly what large-format porcelain wants, so you get big, calm tiles running across the floor with minimal grout lines and a seamless, hotel-like finish.
It’s slightly dearer than a point drain — the channel and its trap cost more, and the setting-out is more exacting — but it’s comfortably our most-requested option. A wall-hugging channel also keeps the drain out of the middle of the floor, and copes well with long, thin shower zones where a central gully struggles.
They also suit walk-in shower layouts where the channel sits at the threshold, and pair naturally with the larger tiles on our bathroom tiling & flooring page.
Wall drain
The channel sits flush against a wall, so the whole floor tilts gently toward that one edge. The tidiest look, and the easiest single-plane fall to tile with big porcelain.
Threshold drain
The channel runs across the shower entry, catching water before it travels into the rest of the room. Handy in open layouts where the wet zone flows into the dry.
Tile-insert channel
A version with a recessed top that takes a strip of your floor tile, so the drain almost disappears. The most discreet finish going.
Flow rate, depth and tying into the waste
Beyond the look, three practical things decide whether a drain works day to day: how fast it carries water away, how much depth it needs under the floor, and how it connects to your existing waste. The parts that don’t show but make or break the room.
Flow rate — keeping up with the shower
A drain has to clear water at least as fast as the showerhead delivers it, or the floor floods before it drains. A modern rainfall head moves a lot of water, so we match the drain and its outlet to the flow you’re actually installing — a punchy shower needs a higher-capacity gully or a longer channel, not the smallest one on the shelf. It’s why a well-fitted wet room floor never pools even under a powerful shower.
Trap and access for cleaning
Every wet room drain has a water trap — a small reservoir that blocks drain smells from rising into the room, exactly like the trap under a sink. It has to stay topped up and reachable. We fit drains with a removable grate and a lift-out trap so hair and debris can be cleared in seconds without tools. A drain you can’t clean eventually blocks, so easy access is non-negotiable on our jobs.
Low-profile depth for upstairs
Under every drain sits the trap and pipe run, and that build-up needs vertical space. On a solid ground floor there’s usually room to spare. Upstairs, on a timber floor, depth is tight — you’re working within the joist zone and protecting the head height of the room below. That’s why low-profile drains exist: shallow traps designed to fit a timber floor without dropping the ceiling underneath. Choosing the right one is central to any tanked upstairs wet room.
Tying into the existing waste run
Wherever possible we connect the new drain to your existing soil or waste pipe — cleaner and cheaper than new routes. But level access often means the finished floor sits lower than the old waste, so we re-route or drop the pipe to keep the right fall along its length. Routine work; it just has to be planned before the floor build-up starts, not discovered halfway through.
How a wet room drain is fitted, step by step
Here’s what actually happens when we set and connect a wet room drain, so there’s no mystery about the work going on under your floor.
1. Position the drain around the falls
First we decide exactly where the drain sits — central for a point drain, or against the chosen wall or threshold for a linear one — based on tile size, room shape and how you’ll use the shower. Everything else follows this.
2. Run and connect the waste
We route the waste pipe from the drain to your existing soil or waste run, keeping a continuous fall so it self-clears. Where the old waste is too high for level access, we drop or re-route it now.
3. Set the drain body and trap
The drain body and its trap are bedded firmly at the low point of the floor, set level and at the exact height the finished tiled floor will meet. Get this height wrong and the tiles never sit flush, so it’s checked and re-checked.
4. Form the falls to the drain
We build the floor’s gradient — via a pre-formed sloped former or a hand-ruled screed — so every part of the floor tilts toward the drain. A point drain falls from four sides; a linear drain falls in one plane. A level confirms it before we go on.
5. Tank and bond the drain flange
The waterproof membrane goes down over the falls and, critically, is lapped and bonded onto the drain’s flange so the tank and drain become one continuous seal. This joint is where cheap jobs leak, so it gets reinforcing tape and careful detailing.
6. Tile up to the grate and test
Floor tiles are cut to follow the falls neatly into the drain, the grate or tile-insert channel is set flush, and we run the shower to confirm water races away with no pooling before handover.
The whole drainage element sits inside a wider wet room build that runs 4–7 working days on site — the curing time for the falls and tanking is the part we won’t rush.
Which drain is right for your room?
There’s no single winner — the right drain falls out of three things: the tiles you love, the shape of the room, and your budget. Here’s the honest guide we use with customers.
Choose a point drain if…
- You want smaller-format tiles or mosaics on the floor.
- Your shower zone is roughly square.
- You’d like to keep the cost down without cutting corners on the waterproofing.
- You like the extra grip more grout lines give underfoot.
Choose a linear drain if…
- You want large-format porcelain and that seamless, minimal look.
- The shower zone is long and narrow, or open to the rest of the room.
- You’d rather the drain sat against a wall or the entry than mid-floor.
- You’re happy to spend a little more for the finish.
Tile size is really the deciding factor: big tiles need the single-plane fall of a linear drain, while small tiles and mosaics are happiest around a point drain. The grip side of that choice runs into our guide on slip-resistant wet room flooring. And if budget is front of mind, our Plymouth bathroom cost guide sets the drainage choice against the whole job — Plymouth runs around 9% below the UK average on fitting, so a linear-drain wet room here still tends to undercut the same spec up-country.
Wet room drainage FAQs
Is a linear or point drain better for a wet room?
Neither is universally better — it depends on your tiles and room. A point drain suits smaller-format tiles and mosaics and costs a little less; a linear drain suits large-format tiles, gives a sleeker look and copes better with long, narrow shower zones. Because a linear drain only needs the floor to fall in one direction, it’s the usual choice when you want big porcelain tiles.
Why does drain type affect which tiles I can use?
A point drain makes the floor slope in four directions toward a central gully, so you need tiles small enough to follow those changing planes — mosaics and smaller formats work best. A linear drain only needs a single-direction fall, so large rigid tiles lie flat and clean. That’s why big-format porcelain floors almost always pair with a linear channel.
Can I fit a wet room drain upstairs on a timber floor?
Yes. Upstairs, depth under the floor is limited by the joists and the head height of the room below, so we use a low-profile drain with a shallow trap designed to fit within a timber floor. We check the joist depth and waste route at survey, then tank the whole zone so there’s no risk to the ceiling underneath.
How is the drain connected to my existing waste?
We run the waste pipe from the drain to your existing soil or waste run, keeping a continuous fall along the pipe so it self-clears. Because level access often puts the finished floor lower than the old waste, we frequently re-route or drop the pipe to hold the right gradient — routine work, but it’s planned before the floor build-up begins.
Does a linear drain cost more than a point drain?
Yes, a little. The channel and its trap cost more than a single gully, and setting it out to a clean single-plane fall takes more care. It’s a modest premium within the overall job, and most people feel the seamless large-format finish is worth it. Our Plymouth cost guide shows where drainage sits in the wider budget.
Proud of every bathroom we fit
Not sure which drain suits your room?
Tell us about your bathroom and the look you’re after. We’ll visit, check the floor structure, head height and waste run, and recommend the right drain and tile pairing — then put the whole wet room on one clear written quote. No surprises, no pressure.