A shower drain used to be a round chrome disc in the middle of the floor, and nobody gave it a second thought. Today the long, narrow channel along one edge of the shower is the signature of a modern bathroom — and it isn't just a style choice. A linear shower drain changes how the whole floor gets built, which tile you can use, and whether a curbless entry is even possible.
Here's how placement, slope, length and flow actually work — and when a centre point drain is still the smarter buy.
Why linear drains and large-format tile go together
A centre point drain needs the floor to slope toward it from every direction — a compound slope of four subtly warped planes that rigid large tiles can't follow. It's why point-drain floors are almost always mosaic: only small tiles on mesh backing can bend around the geometry.
A linear drain replaces all of that with one flat plane tilted gently toward the channel. Because the plane is flat, any tile works: 12 × 24 porcelain, big-format slabs, even the bathroom-floor tile running straight into the shower. Fewer grout lines look better and mean less scrubbing, too.
The pitch itself doesn't change — roughly 2 per cent, about 1/4 inch per foot — but it's one slope in one direction, which is exactly what large tile and a barrier-free, curbless entry need.
Placement: back wall, entry or centre of the floor
There are three sensible places to put a linear drain, and the choice affects both looks and plumbing.
| Placement | How the floor slopes | Best for | Worth knowing |
|---|---|---|---|
| Against the back or side wall | One plane, away from the entry | Most installs; the cleanest look | Drain line usually has to move to the wall; plan for plumbing work |
| At the entry (threshold) | One plane toward the door | Curbless showers where stray water is the top concern | Acts as a moat at the opening, but you step over it every time |
| Centre of the floor | Two gentle planes toward the line | Reusing an existing centre drain rough-in | Less common; you lose some of the single-plane tiling advantage |
The back-wall position is the default for good reason: water runs away from the glass and the doorway, the drain tucks out of sight, and the tile layout is dead simple. Entry placement suits curbless bathrooms — nothing escapes past a channel spanning the doorway.
Length: cover the opening, or go wall to wall
The working rule: the drain should span the water it's meant to catch. Water fans out as it travels down the slope, so a channel much shorter than the shower lets water sneak around its ends into the corners.
- Wall to wall is the most foolproof and, to most eyes, the best-looking. Drains come in graduated lengths from roughly 24 to 60 inches, so you can usually land close to the finished dimension.
- Shorter than the wall works if the drain at least spans the shower opening and is centred on it; the tile cuts at each end take a more careful installer.
- At a curbless entry, the channel should span the full opening — a gap at either end is a gap water will find.
Measure at the finished-tile stage, not off the framing, and check how the manufacturer states length — some quote the channel, others the overall flange.
Flow rating: add up your shower, then buy above it
Every linear drain lists a flow capacity in litres or gallons per minute. A single Canadian showerhead, flow-restricted by regulation, is easy work for nearly any channel drain. The math changes with custom setups: a rain head, handshower and body jets running together move several times that water. If you're speccing a multi-outlet shower system, add up the maximum simultaneous output and choose a drain rated comfortably above it.
Two honest caveats: the trap and waste pipe below matter as much as the channel — a high-capacity drain into an undersized line still backs up — and hair screens reduce real-world flow, so a little headroom in the rating is cheap insurance.
Tile-in or grate top?
The visible part of a linear drain comes in two flavours:
- Grate tops show a stainless surface — slotted, perforated or patterned. They lift out easily for cleaning and come in finishes like brushed stainless and matte black to match your fittings.
- Tile-in (tile insert) tops hold a piece of your own floor tile in a shallow tray, so the drain nearly disappears — all you see is a slim slot around the edges. The catch: your tile has to suit the tray depth, the insert is fussier to lift out, and cutting the infill piece cleanly is precision tile work.
Neither drains better. It's a question of whether you want to see the drain, and how much you trust your tile setter.
Waterproofing: buy the drain and the membrane as one decision
This is where linear drains are won or lost. The drain's flange has to bond or clamp to your waterproofing method — bonded sheet membrane, liquid-applied membrane, or a traditional liner — and drains are built for specific methods. A drain mated to its matching membrane system is a tested assembly; mixing one brand's drain with another's membrane is where leaks are born.
Decide on the waterproofing system and the drain together, and follow the manufacturer's installation sequence exactly. Going curbless adds one more layer: the subfloor typically has to be recessed so the finished shower plane lands below the bathroom floor. None of this is a place to economize.
When a centre point drain is still the practical pick
Linear drains are wonderful, but they aren't a moral obligation. A centre point drain remains the sensible choice when:
- The plumbing already lives in the centre. Moving a drain line in a concrete slab, or above a finished ceiling below, is real money. Reusing the existing rough-in can fund nicer tile or a better valve.
- You're using a prefab base. Moulded shower bases come with the drain location decided for you, and matching your existing rough-in matters more than drain fashion. Our guide to shower base sizes and drain placement walks through exactly that.
- You actually want a mosaic floor. Pebble and penny-round floors handle a compound slope effortlessly. If that's your look, the point drain costs you nothing.
- The budget is tight. Between the hardware and the extra labour in sloping and waterproofing, a linear installation costs meaningfully more than a conventional point-drain shower.
In other words: choose the floor you want first, then the drain that builds it. When you're ready to compare channel styles, lengths and finishes, our drains collection covers both linear and point options.
Frequently asked questions
How much slope does a linear shower drain need?
The standard is about 2 per cent — roughly 1/4 inch of drop per foot — across a single plane toward the drain. Confirm against your local plumbing code and the manufacturer's instructions before you build.
Does a linear drain have to run wall to wall?
No, but it should be at least as long as the opening it protects and centred on it. Wall to wall is the most forgiving layout and the easiest to tile cleanly, which is why most designers default to it.
Can I get a linear drain with a prefab shower base?
Yes — several manufacturers mould bases with a trench-style drain along one edge, so you get the look without site-built waterproofing. The base dictates the drain location, though, so match it to your existing rough-in first.
Are linear drains harder to keep clean?
Different, more than harder. The grate or tile insert lifts out for access to the full channel, and most models include a removable hair strainer. Rinse the channel and clear the strainer every few weeks and it stays trouble-free.