Installing a wet room shower tray may seem intimidating at first, but it’s actually quite straightforward. The process is similar to installing a regular shower tray, with some key principles to keep in mind: the tray must be level, there should be enough space for the waste pipes, and everything needs to be fully watertight. The main difference with a wet room tray is that it’s installed flush with the floor, which requires additional work on the floor and subfloor. The wet room tray serves as a watertight base, designed to be tiled with a slight slope to ensure proper drainage.
If you’re installing a shower tray on a wooden floor, these instruction will show you how to get the best results. This is a simple DIY task which is made easy with the use of a wet room shower tray former, which acts as a template for creating a level, watertight base. The wet room shower tray former is designed to be installed flush with the floor, allowing tiles to be laid directly on top with a gentle slope toward the drain. It ensures that water drains efficiently while maintaining a seamless, sleek appearance.
By using a shower tray former, you eliminate the need for complex leveling work, making the installation process smoother and ensuring a professional-looking, watertight finish in your wet room.
Table of Contents
Step One. Organise your Tools and Materials
Before you get started, ensure you have the correct tools to complete the job. A spirit level, pencil, tape measure, jig saw, paintbrush and notched trowel.
You’ll also need some materials including a suitable shower tray former, tiles, tile adhesive, some OSB or ply boards and tile grout for finishing the tiling. The shower tray will need to be installed flush with the flooring so ensure you measure and select the correct one. Most shower trays will be available between 20 – 40mm thicknesses.
Step Two. Location
Now it’s time to mark the floor area around the shower tray. You can measure this out using a tape measure and pencil or you can simply lie the tray on the floor and draw around it.
It’s also important at this point to ensure you have suitable waste pipe access and flow. Can you extend any existing waste pipe to this area of the room? Water will need to flow down the pipes to the main waste stack, so be sure you have a suitable length and flow angle to achieve this. Pipes with a gradient of between 1/40 and 1/110 should be sufficient to prevent blockages. (1/40 is 1cm drop for every 40cm, 1/110 is 1cm drop for every 110cm)
Step Three. Cutting the Floorboards
To ensure the wet room shower tray sits low enough on the floor you will need to cut and remove any existing floorboards. Following the pencil marks drawn around the shower tray, cut the boards using a jigsaw or multi-tool. Now remove the floor boards to reveal the timber joist below.
Floorboards are normally around 20mm thick. Some may be 22mm thick or maybe more. Ensure you measure this depth and order the correct shower tray that aligns with this depth. Your wet room shower tray thickness should equal the thickness of your floor boards.
Step Four. Waste Trap
The waste trap will need to be secured to a ply or OSB platform underneath the level of the timber joists. Measure and cut a suitable piece of board and secure it into place underneath the joist line.
Perform a water flow test to ensure the waste trap is positioned correctly. The height of the waste trap will align with the bottom of the shower tray.
Step Five. Building a Plywood Floor
We now need to create a plywood floor that is flush with the top of the joists. To do this, use 25x50mm battons aligned along each side of the timber joists, just 22mm below the top.
Cut some marine ply to the width of the joist span and secure them flush with the top of the joist. Cross support beams can also be used for extra strength.
Ensure you leave a hole to access the waste tray below.
Step Six. Fitting the Wet Room Tray
Dry install the tray before you go any further. Check that everything is level and the heights are correct. The tray will need to fit flush with your floorboards ready to be tiled over.
Now remove the tray and spread tile adhesive using a notched trowel across the newly laid floor. Slowly lower the tray onto the new floor and adhesive and connect the waste trap using the fixings supplied. Some silicone or pipe sealant may be required to finish the join.
Check the floor again with a spirit level and adjust as required. The tray should be installed flush with the level of the floor so that a nice simple tile can be installed to complete the look of the room.
Step Seven. Sealing and Tiling
The final stage of this project is to ensure a water-tight finish around the tray. Using a pro sealer paint and sealer tape you can apply a lining around the edges of the tray to prevent any water escaping. This will provide a nice seal before tiling takes place.
You can now complete the installation with tiling, ensuring the flooring is completed first, followed by the walls.
Conclusion
installing a wet room shower tray is a manageable DIY project when broken down into clear steps. By ensuring you have the right tools and materials, preparing the floor properly, and focusing on a level, watertight finish, you can create a sleek, functional wet room.
The main challenge lies in ensuring the tray sits flush with the floor and that the drainage system is correctly aligned to prevent any future issues. Once the tray is securely installed, the final sealing and tiling steps will give the room a polished, waterproof finish, ready for use. With attention to detail and careful planning, this project can transform your bathroom into a modern, practical space.
