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How to install a wet room shower

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A wet room is a great way to utilise a smaller bathroom and relatively straight forward to install. Our step by step animated video is designed to help inspire your next wet room project, showcasing the fundamentals required in a wet room shower design.

The video demonstrates how to install a wet room by maintaining your floor’s height and installing a linear drain design. However, creating a wet room isn’t always this simple depending on your foundation. In this guide we further break down the steps to maintaining the floor height as well as raising the floor height and utilising an existing concrete floor. We’ll also take you through waterproofing your wet room and installing square and linear drain designs.
Tools for the job
Circular and Jig saws | Drill or cordless screwdriver and screws | Spirit level

Tape measure and pencil | 4-6mm square notched trowel | Notched trowel suitable for tiles

Margin trowel | Mixing bucket | Flexible cement-based tile adhesive

Grout | Sealant adhesive | Waterproofing

Drain trap and grate | Wet room tray
Maintaining your floor’s height

1 - Clear the selected area and make sure the floor and walls and secure and clean from dirt and debris. Lift the boarding to establish where the joints are positioned and check for existing pipework and cables that may cause obstructions. 2 - Work out the best position for the wet room tray to allow the drain to sit between two joists. The tray can be set down along the wall edge or spaced away from the wall using plywood or construction board to fill the gap. If using infill pieces at the perimeter, make sure the gradient of the tray is followed to avoid water pooling. Mark the position of the tray on the floor and remove it. 3 - Set a circular saw to the depth of the floorboards and cut a recess for the tray to fit in. When cutting across the joists, the floorboards will need to be cut back to the centre of the next joist so that the floor is properly supported. Check the joists with a spirit level and re-level with packing timber or a chisel f necessary (the floor needs to be level for the gradients of the tray to work). 4 - Mark a horizontal line 18mm down from the top of each joist. Cut and securely screw 1”x2” timber battens so that the 18mm ply infill boards can sit level with the top of the joists.

5 - Cut 18mm exterior plywood boards to fit between each exposed joist. Lay the tray in the recess and mark the centre of the drain hole. Remove the tray and cut a 130mm diameter hole central to the marked position. You need to ensure that the height of the surrounding floor matches the final thickness of your wet room tray, boards or Durabase matting can be used to raise the height. 6 - Lift the cut out board and construct a shelf approx. 90mm down from the top of the infill board/joist, between the joists to position the waste trap. The trap needs to be central to the hole with the rubber seal level or just below the top surface of the surrounding ply board once back in place. The trap itself must not be load bearing. 7 - If using a solvent weld pipe, fit the ring and seal on to the adapter and screw them to the trap. Apply solvent to the adapter and pipe and fit together, securing the pipe with pipe clips or suitable supports. Check the joint is watertight as this area cannot be accessed again once the tray is in place. Then check the trap position again and screw the infill boards down. 8 - If you’ve had to cut extra flooring away to reach a supporting joist, screw down a piece of the original flooring or a board of equal thickness to fill in the floor, leaving a recess the size of the shower tray.

Raising your floor’s height
Suitable for installing a wet room tray on top of the existing floorboard height, this type of installation allows for the surrounding floor to be boarded with ply or insulation/construction boards.

1 - The floor must be secure, completely free of movement and level. Clear the area and clean it up then lift the floorboarding to establish the joist positions and check for existing pipework and cables which may cause obstructions. 2 - Work out the best position for your tray, allowing the drain to sit between two joists. The tray can be set down along the wall edge or spaced away from the wall using plywood or construction board to fill the gap. If using infill pieces at the perimeter, make sure the gradient of the tray is followed to avoid water pooling. Once positioned, construct a shelf, approx. 90mm down from the top of the existing floor. The trap will sit on this with the rubber seal level or just below the top of the surrounding floorboards once back in place. The trap itself must not be load bearing. 3 - Before connecting the trap, loosely lay the floorboarding back in place and use the tray to mark the drain hole, remove it and then cut a 130mm diameter hole central to the marked position. Take the floorboards back up to access the waste connections. 4 - If using a solvent weld pipe, fit the ring and seal on to the adapter and screw them to the trap. Apply solvent to the adapter and pipe and fit together, securing the pipe with pipe clips or suitable supports. Check the joint is watertight as this area cannot be accessed again once the tray is in place. 5 - Fix the floorboards back down leaving the trap positioned through the previously cut hole. Securely fix the floor down with screws.

Utilising an existing concrete floor
If you’re working with an existing concrete floor and the surrounding floor will be boarded over with insulation and/or construction boards then you can install your wet room shower following this method.

1 - Check for existing pipework and cables in the concrete which may obstruct the route of the new waste pipe and identify the best orientation for the wet room tray. Clear the selected area and ensure the floor and walls are clean, free from dust and debris. 2 - Check the floor with a spirit level and level it out with a levelling compound if necessary. 3 - The tray can be set down along the wall edge or spaced away from the wall using plywood or construction board to fill the gap. If using infill pieces at the perimeter, make sure the gradient of the tray is followed to avoid water pooling. Using the tray as a template, mark the drain position and chisel the concrete away to fir the trap and waste pipe. The rubber seal of the trap should be level with the existing floor surface but the trap should not be load bearing. 4 - Connect the trap to the waste pipe, checking it’s still in line with the hole in the tray. If using a 43mm solvent weld pipe, fit the ring and seal on to the adapter and screw them to the trap. Apply solvent to the adapter and pipe and fit together. Check the joint is watertight as this area cannot be accessed again once the tray is in place. 5 - Fill around the pipe and trap with concrete or expanding foam. Before set in position, double check the trap lines up with the hole in the tray and the threaded ring can be screwed through the tray into the trap.

Waterproofing your wet room
Waterproofing and sealing against water and moisture are a crucial part of installing your wet room. It's also advised for any wet area in a bathroom, such as a shower, whether you're using a tray or creating a wet room floor from tiles.

Here's our quick how-to video on what waterproofing should look like, you can then follow our detailed step by step guide below.

Waterproof matting creates a 100% guaranteed seal but you can also use other methods such as a liquid waterproofing membrane like BAL's Waterproof 1C.


Pre-cut all your matting to size before installation, ensuring to measure your areas carefully before cutting.


Start by fitting the wall matting first, working from the edge of the room ensuring to trowel the powder-based adhesive in straight lines using the 4-6mm notched trowel (this ensures all air bubbles are removed from underneath the matting).


Lay the pre-cut matting (non-printed side down) and work the matting firmly into the tile adhesive with the flat edge of the trowel. Remove and excess adhesive and eliminate any air pockets.


Using the trowel, apply the adhesive evenly to each side of the joint and install joint tape, evenly overlapping the joint then smooth it out.


Then move on to your floor. Where the tray will be going up against two walls, you can cut a square of matting from the corner of the tray to enable the sides to fold up and meet in the middle. You can then follow the same laying process as the walls.


The final step is to fit the matting joints, using the notched trowel apply the adhesive approx. 75mm wide on the floor and wall where the corner joint tape will be applied. Position the tape and securely firmly with the flat edge of the trowel. You can then follow this process with the joint tape around the edge, ensuring that both the adhesive and tape overlap the corner joint pieces by 50mm.


You can also use a pipe collar to seal around external pipes like the shower’s water pipe.

Installing square or linear drains
Based on the shape of your drain, a square and linear drain require different fitting techniques, see below which one applies to your drain type.
Square drains

1 - Screw the threaded ring into the trap using the key to tighten it. If the trap isn’t tight up against the bottom of the tray, use the wire lifter supplied to raise it whilst screwing the top ring. Pour water into the drain hole to check for any leaks before concealing the plumbing again. 2 - Drop in the hair catcher and cover and then screw the drain body to the height of the floor tiles being used. The metal frame should sit just below the final tile height to ensure the water doesn’t pool around the drain. 3 - With the flat edge of a trowel, pack tile adhesive up against the drain body to provide further support and hold in place. 4 - You’re then ready to tile and grout the floor around the drain, take care to wipe away any excess adhesive and grout from the drain body. Then you can place the grate.

Linear drains

1 - The drain body is height adjustable to suit floor tiles (from 6-16mm thickness), if your tiles are greater than 7mm, use the self-adhesive spacers supplied to raise the drain body. Peel back the tape backing and stick to the matting under the drain body. 2 - Place the metal drain body in its footprint and screw the threaded centre ring into the trap below using the key to tighten it. Pour water down the drain hole to check for any leaks before concealing the plumbing. 3 - Tile and grout the floor, ensuring to remove any excess adhesive and grout. Drop in the hair catcher and cover and then place the grate into the drain body.

How to install a wet room shower