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Tileable Shower Trays: Sizes, Fitting and Waterproofing

What a tileable shower tray is, how to choose size and drain position, what the floor needs, and where tanking matters, from a Cardiff bathroom fitting team.

Tileable Shower Trays: Sizes, Fitting and Waterproofing

Tileable shower tray ready for waterproofing

A tileable shower tray is a shower base that you tile over, instead of a raised acrylic or stone resin tray that is already finished. It has a built-in slope to the drain, sits flush with the floor and lets your bathroom floor tiles run straight into the shower. It looks far better than a standard tray, but it only works if the floor beneath it, the waterproofing and the drain position are right. This guide covers what to check before you buy, and where jobs usually go wrong.

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TL;DR

  • A tileable tray (also called a tray former) is a pre-sloped, waterproof base you tile over, so the shower floor can match the rest of the room.
  • Choose the size from finished wall measurements, and choose the drain position to suit your existing pipework before you pick the tray.
  • The tray needs full support underneath. On a timber floor that usually means strong, level plywood, not old chipboard.
  • The tray is not the waterproofing. The shower area, a further 300mm splash zone and the walls still need tanking before any tile goes on.
  • Swapping an existing tray without disturbing tiles is rarely possible. Plan on retiling the edges.

Table of Contents

What a tileable shower tray actually is

A standard tray is a finished product. Acrylic-capped ABS or stone resin arrives with its surface ready to use, and a moulded acrylic or composite base cannot be tiled. A tileable tray is different. It is a base made to receive tile, with an edge profile designed to work with a waterproofing membrane and adhesive.

UK manufacturers describe the product in similar terms. One March 2025 UK catalogue describes it as a lightweight, flush-floor panel with pre-formed falls to the drain and a cementitious coating ready for floor tiles. Retailers also call these products shower tray formers: a waterproof base that blends with the bathroom floor once tiled.

The practical differences from a standard tray:

Standard acrylic or stone resin tray Tileable tray (tray former)
Surface Finished, cannot be tiled Tiled by the installer
Height Raised above the floor Can sit flush, a continuous wet-room floor
Look Visible white or colored tray Same tiles as the floor, if you want
Sizes Fixed catalog sizes Fixed sizes, some can be trimmed
Install Bed, level, connect waste Support, fix, tank, then tile
Repair Replace the tray Re-grout, re-seal or lift tiles

The trade-off is preparation. A tiled tray offers seamless floor tiling but needs proper preparation and waterproofing. A flush tray done badly costs far more to fix than a standard tray done badly, because the fault sits under tile.

Is a tileable tray right for your bathroom?

It suits you if:

  • You want a walk-in or level-access shower that looks like part of the floor.
  • You are renovating anyway, so the floor is open to inspection and the tiling is being redone.
  • You have an awkward room shape, where a made-to-fit or trimmed base beats a catalog tray.
  • Accessibility matters now or may later. A low or flush threshold is much easier to step over, and we cover that in our guide to a wet room for elderly relatives.

It is a poorer fit if:

  • You only want to replace a cracked tray and keep the surrounding tiles. More on that below.
  • The floor is weak, damp or badly out of level and you do not want to fix it.
  • The waste cannot be moved or lowered enough for the fall you need.

If you are still weighing up shower designs generally, our walk-in shower ideas for UK homes will help you decide what you want before you get into the technical detail.

Sizes, shapes and drain positions

Standard tray sizes are a good starting point because tileable ones follow similar footprints. A UK buying guide lists square, rectangular, quadrant, offset-quadrant, D-shaped and bespoke formats, with examples such as 800 × 800 mm, 900 × 900 mm, 800 × 1200 mm and 900 × 1200 mm. Walk-in trays run longer, up to 900 × 1850 mm in the same guide. Answering the common search question: there is no single standard size, but 800 × 800 mm and 900 × 900 mm squares and 1200 × 800 mm or 1200 × 900 mm rectangles are the sizes you will meet most often.

Common shower tray footprints and dimensions

Measure after the walls are finished

The most common error is measuring too early. Take measurements against finished wall surfaces, and leave a 2 to 3mm tolerance for silicone sealing. The same guide warns that wrong measurements can cause alignment errors, leaks or water pooling. On a tileable tray the walls may still be unfinished when the tray goes in, so agree with your fitter what thickness of tile and adhesive will be added to the walls and allow for it.

Some bases can be trimmed on site. One manufacturer’s FAQ says its base can be trimmed up to 50mm from each edge, but equal amounts must come off opposite edges to keep the pre-formed fall working. Check the instructions for the exact product before anyone picks up a saw.

Choose the drain position first

The drain decides what is possible, so work it out before ordering. Options are:

  • Centre drain: a point drain in the middle. It works best in a square or near-square shower where the fall runs from all four sides.
  • Offset or corner drain: the drain sits toward one side or corner, which helps when joists or the existing waste are in the way.
  • Linear drain: a channel along a wall, often with a single-direction fall. It suits walk-in showers and large format tiles, and lets you route the outlet along the channel around joists or other underfloor obstacles.

Whatever you choose, the drainage must match the existing plumbing and drainage. Moving a waste is possible, but it costs more and depends on the floor construction. Ask for the waste route to be checked before you commit.

Height matters too. One UK system lists installation heights from 0 mm to 130 mm including drainage, which shows how much the choice of product and drain type changes the build-up you need to find in your floor.

What the floor needs before the tray goes in

A tileable tray must be fully supported. That is the single biggest reason jobs fail. If the base flexes, the grout above it cracks, and water finds its way through. Do you put flooring under a shower tray? Yes: one manufacturer states its base must be fully supported underneath, recommending 18mm marine plywood.

Timber floors

Many Cardiff and Vale homes, especially terraces and older semis, have suspended timber floors upstairs. The substrate needs to be flat, level and load-bearing. For one major membrane-and-drain system, the installation instructions suggest replacing unsuitable P5 or green chipboard with 18mm exterior-grade plywood. The same instructions say tiles smaller than 300mm x 300mm or thinner than 8mm should not be used unless the sub-floor is strengthened with the specified accessory. Small mosaics on a wooden floor are not a casual choice.

We have written more about this in our articles on a wet room on a wooden floor and whether you can have a wet room on a wood floor.

Concrete floors

On a ground floor with concrete, the problem is depth for the waste. One manufacturer’s answer is to mount the base on a raised platform or a channel chased into the concrete so that the drain and waste pipe sit at the correct depth. A raised platform means a step. A channel means breaking out concrete. Neither is a surprise if you ask early.

Waste pipe channel cut into concrete floor

Before any work starts

Clear the area and check for pipes and cables where you intend to cut or fix. The steps for a wet-room shower begin with clearing the area, checking for pipework and cables and preparing the floor for its structure. Lift a floorboard or two. Look for water damage on joists, because a leak under an old tray will have left evidence there.

Waterproofing: the tray is not the whole answer

Homeowners often assume a tileable tray is waterproof, so the rest of the bathroom does not need attention. Tile and grout are not waterproof. The tray is the base, and tanking is the system around it.

The guidance is consistent: the full showering area, a further 300mm splash zone and the shower walls need to be tanked before tiling, with matting joints sealed with joint tape. Tanking creates a waterproof barrier across walls and floors, typically using a liquid membrane or waterproof matting.

A few practical points we stress on jobs:

  1. Follow one system. Tray, membrane, tape, drain flange and adhesive are designed to work together. Mixing parts from different makers is how warranties and waterproofing both fail.
  2. Test the waste joint before you hide it. Fill, check, and leave it for a while. The check is far cheaper than lifting tile later.
  3. Seal the edges and corners. Movement joints between wall and floor need flexible sealant, not rigid grout.
  4. Do not cut corners on the splash zone. Water goes beyond the screen line more often than people expect.

The plumbing side is also covered by regulation, and proper levelling and professional installation help prevent micro fractures, which one UK supplier ties to Building Regulations Part G. Ask any installer how they will test and document the waste and the tanking.

Adhesive, tile choice and grout

The tray needs the right adhesive. For one product, the instruction is to use flexible tile adhesive mixed from powder and to avoid solvent-based and ready-mixed adhesives. Different makers have different requirements, so read the datasheet for the specific tray.

On tile choice:

  • Small tiles give more grip underfoot and follow falls easily, but have more grout lines to maintain. On a timber floor, remember the minimum size warning above.
  • Large format tiles look sleek, but on a sloped tray they need to be cut and laid carefully to follow the falls. Linear drains with single-direction falls suit them better.
  • Choose a slip-resistant finish for the shower floor, not a polished one.

If you want a plain explanation of how setting beds and joint fillers differ, this explainer on grout versus mortar is a helpful starting point. Once the job is finished, treat grout and sealant care as routine. Keep grout lines clean and reseal or regrout as part of regular maintenance.

Can you change a shower tray without removing tiles?

Often not. On a conventional tray, tiles on the walls usually sit on top of the tray edge with a silicone seal. Tradespeople answering a homeowner’s question on a UK quotes site disagree on the details, but the common view is that you will usually have to take some tiles out. A tray can only slide out if the trap is reachable and the tiles are not sitting on it, which is the exception.

For a tileable tray the answer is more definite. The tiles are laid over the tray, so replacing it means lifting the floor tiles and, normally, the lower row of wall tiles. If you are swapping an old standard tray for a new tileable one, plan for retiling the shower area and a new tanking layer. Our advice is to treat it as a small renovation instead of a swap. If you cannot find matching tiles, use a contrasting border or retile the whole shower wall and make it a feature.

What it costs

Tileable trays are only part of the bill. The price of the tray itself varies by size and system, while the labor for support, waste work, tanking and tiling makes up most of the job. We publish one figure: a full bathroom renovation with us is £2,500 to £4,000 as a one-off project price. A wet room or tray conversion can sit inside that kind of project, depending on the floor, waste and tiling. We quote every job in writing after seeing the room, because the floor structure is what moves the price.

Our view: where tileable tray jobs are won or lost

We fit bathrooms and wet rooms across Cardiff and the Vale of Glamorgan, and we would rather tell you what we think than sell you a tray. The product is rarely the problem. The problems are almost always hidden: a spongy floor, a waste that cannot get its fall, tanking that stopped at the screen line, or tiles chosen without thinking about the slope.

So we do things in a set order. We look at the floor and the waste first, then choose the tray and drain to suit, then agree the tile with the fall in mind. One accountable team does the plumbing, the tanking and the tiling, instead of handing the job between trades. That matters on a tileable tray because every layer depends on the one beneath it, and nobody can blame the last trade when water appears.

Our honest advice: if you want the flush, seamless look and are happy to do it properly, a tileable tray is worth it. If you only want a quick swap and nothing else disturbed, a standard tray is the more sensible choice.

— James

Need a tileable shower tray fitted in Cardiff or the Vale?

We handle the whole job: the floor, waste and plumbing, tanking, tiling and finishing. See our wet room conversions and installations, or look at our bathroom fitters in Cardiff and bathroom fitters in Barry pages. If the tiling is the part you want help with, our tiling services cover that too.

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FAQ

What is the difference between a tileable tray and a wet room tray?

The terms overlap heavily. Both mean a pre-sloped base that is tiled over. “Wet room tray” usually points to a flush, walk-in format with a linear or centre drain, while “tileable tray” is the broader name for any base designed to take tile.

What is the standard size of a shower tray?

There is no single standard. Square 800 × 800 mm and 900 × 900 mm and rectangles such as 1200 × 800 mm and 1200 × 900 mm are the most common sizes. Walk-in formats run longer, and some bases can be trimmed slightly to fit.

Which is better, acrylic capped ABS or stone resin?

For a standard tray, stone resin feels more solid and is usually thicker and more expensive, while acrylic capped ABS is lighter and easier to handle. Neither can be tiled. If you want a tiled shower floor, you need a tileable tray instead.

Can I tile a tileable tray myself?

You can tile it, but the support, tanking and waste connections decide whether it leaks, and a fault is hidden under tile. We recommend a qualified fitter for the waterproofing, and a plumber for the waste.

Does a tileable tray need tanking?

Yes. The shower area, a further 300mm splash zone and the walls should be tanked before tiling, following the maker’s system instructions.

Sources

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Tileable Shower Trays: Sizes, Fitting and Waterproofing