By Kerry Hale

How To Fit A Shower Tray So It's Watertight

  • Wednesday 03 November 2021
  • 7 minute read

The shower tray is a vitally important part of the shower. It’s essential to pick one that is well-built and will last over time, but the quality of the tray will count for very little if it’s poorly installed. Fitting a shower tray correctly can be the difference between a smoothly running, watertight bathroom and costly leaks. Fear not, we’ve got you covered in our guide on how to fit a shower tray below.

The different types of shower trays

There are essentially two different types of shower trays:

Low profile trays

Low profile shower trays are designed to sit as low to the floor as possible. If you want a step-free shower that you enter at ground level, then you’ll need a low-profile shower tray. You can also refer to these types of shower trays if you want to know how to install a wet room shower tray.

Adjustable height shower trays

Adjustable height shower trays stand on adjustable legs and are useful in that they can be lowered or raised to your desired height and allow easy access to the pipes underneath in case of leaks or if anything needs replacing.

We always advise fitting the shower tray before tiling the walls or installing wall panels as this ensures a more watertight seal around the sides of the tray.

What you’ll need to install a shower tray

Before you start installing your shower tray below is a list of things you will need:

  • A pencil
  • A spirit level
  • A drill
  • A jug or kettle
  • A hacksaw/jigsaw
  • Silicone sealant
  • Sealant gun

Additional things you’ll need for fitting a low-profile shower tray:

  • Cement
  • Building sand
  • Mortar trowel

How to fit an adjustable height shower tray

Follow the steps below to fit an adjustable height shower tray:

  • Step 1 - Position the shower tray where you want it installed and make sure it fits into the space with no clearance issues. Screw the legs into position and adjust the height until the tray is at the desired level. Attach the tray’s waste outlet to make sure that everything lines up properly.
  • Step 2 - Ensure the riser legs are adjusted to allow an adequate fall for the waste to drain away, typically 50mm fall per metre length of pipework. Initially, it may be easier to get the tray level by adjusting the key corner legs first. And don’t forget to fit the centre leg.
  • Step 3 - Work out the best route to the waste pipe from the waste trap in the tray. If your outlet pipe is already in place, connect this to the trap.
  • Step 4 - Place the tray, having pre-fitted the bottom part of the waste to the pipework.
  • Step 5 - Use a spirit level to ensure that the tray is completely level the whole way around. This is one of the most important steps in installing a shower tray as a tray that isn’t level will cause issues with drainage and water could gather on one side of the tray and potentially overflow. Trays are designed so that the water runs towards the waste outlet, so there’s no need to tilt the tray.
  • Step 6 - Check all of the legs are engaged and that the lock nuts are tightened up and touching the flange
  • Step 7 - Get a kettle or jug of water and pour it down the shower drain to see that it all flows through without any drips or leaks.
  • Step 8 - Cover up the gaps around the sides of the tray using either skirting boards or shower tray side panels.
  • Step 9 - Run a bead of sealant first behind the tray between the wall and tray, to cushion the tray and as a primary seal against leaks. Apply a bead of sealant along the top edge and wall.
  • Step 10 - Fit the tiles leaving a gap (approx. 3mm) between the tray and tiles. Run a bead of sealant between the bottom of the tile and tray, ensuring it penetrates the gap. This secondary seal is important.
  • Step 11 - Cut the side panels to length. Fix the leg clamps in place on legs prior to offering up the panel. You may wish to fix battens on the floor to secure the panel.

How to fit a low-profile shower tray

Follow the steps below to fit a low-profile shower tray:

  • Step 1: The floor beneath your tray will need to be completely secure so position the shower tray where you want it to go and test that the floor is strong and solid enough to support it without movement. If it’s not, then remove the floorboards from this area and replace them with marine plywood that is more than 20mm thick.
  • Step 2: Cut an access hatch in your floorboards next to the shower tray so that you can easily access the underneath of the shower tray for maintenance to the pipes.
  • Step 3: By its nature, a low-profile shower tray has no room for pipework between the base of the tray and the floor, so you’ll need to remove part of the floorboards to make room for these.
  • Step 4: Mix up building sand and cement to create a mortar. Spread a thin layer carefully over the area where the shower tray is going to go. Position the shower tray on top of this and use a spirit level to ensure that everything is completely level. Allow to dry for around 24 hours.
  • Step 5: Use the access hatch to connect the waste trap to the outlet pipe and the outlet pipe to the waste pipe underneath the tray.
  • Step 6: Use silicone sealant to ensure a secure, watertight seal the whole way around the tray.

Maintaining a shower tray after installation

In order to maintain your shower tray after you have installed it, regular cleaning can help to prevent a build up of soap scum or limescale. White wine vinegar and baking soda are a quick fix for rust marks. To avoid mildew in your shower enclosure regularly using mould cleaning spray can help to prevent this from appearing in your shower tray sealant.

If you need further help and support, please always refer to our shower trays page to browse all of our Mira products.

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