A Comprehensive Guide to How to Seal a Shower Tray

Wondering how to seal a shower tray or looking for top DIY tips on how best to apply silicone sealant? Room H2O’s expert advisors are here to help …

This is how to apply silicone sealant to shower tray with a neat bead formed with a smoothing tool

One of the most common causes of water leaks from shower trays, shower enclosures and baths is the poor application of silicone sealant. Here are some handy tips to set you on the right path and make sure you apply silicone sealant correctly to achieve a professional finish and prevent water leaks.

Shower tray sealing: the right tools

  • Choose the correct type of silicone sealant that is compatible with your chosen wall or floor coverings (such as natural stone, porcelain tiles or ceramic tiles). Consult the tile supplier or sealant manufacturer for further guidance.
  • Buy a hygienic silicone sealant of good quality. It should specify that it is suitable for use in bathrooms / wetrooms and contain an anti-mould and bacterial additives such as Kerakoll Fugabella Eco Silicone Sealant  or Kerakoll Fugabella AM Silicone Sealant, which are both available from our sister company UK Tiles Direct.
  • Buy a good quality sealant application gun to make applying silicone sealant an even and consistent process. For even smoother results, you could also buy a silicone sealant application tool. Made from rubber and designed to remove excess sealant, these handy tools will help you achieve a neat bead of silicone when sealing a shower tray. The Fugi, produced by Cramer (pictured below), features cut outs of various sizes which produce different bead thicknesses. While this is suitable for use with silicone sealant and caulking, similar good quality tools can be purchased from tile retailers and good DIY outlets.
  • Buy a good retractable utility knife.  A sharp knife will be required for opening the silicone sealant and trimming the application nozzle to size.
  • Make sure you have paper towels and a large plastic bag to hand when shower tray sealing. Silicone sealant is sticky by nature so when smoothing the freshly applied sealant, you will likely need to clean excess from the application tool with paper towel. After cleaning, dispose of the paper towel and make sure your hands are clean.  

Silicone sealant application and finishing tool by Cramer

Preparation is key when sealing a shower tray

  • It is important to read and follow the silicone sealant manufacturer’s instructions. 
  • The sealant must be fully cured before it comes into contact with water.
  • Remove loose deposits and surface dust with a vacuum then, with a damp cloth that has been soaked in a mixture of warm water and mild detergent to remove any stubborn deposits, thoroughly clean and dry the area where the silicone sealant will be applied (the shower tray surface and tiles). 
  • Give the area a final wipe down with a clean damp cloth to remove any residual detergent but do not get the area wet.
  • Thoroughly dry the shower tray area with paper towel or allow the shower tray to air dry for a couple of hours before applying the silicone sealant, which will not adhere properly should any moisture remain.

Top 10 tips for applying silicone sealant to shower trays

1 - Clean the shower tray

Check the shower tray and walls are completely dry and free from dirt, dust, grease and debris or the silicone sealant will not adhere correctly.

Thoroughly clean the shower tray and tiles to ensure the surface is free of dirt and grease before applying silicone sealant

2 - How much silicone sealant to use

If using a tool to smooth the silicone sealant, select the correct aperture size to produce a bead that will fully cover the gap between the shower tray and tiles.

A Fugi silicone sealant application with various sized cut-outs at each corner for achieving various thicknesses of silicone sealant bead

3 - Sizing the sealant application nozzle

The nozzle of the silicone sealant tube will usually feature perforated marks to indicate where and how to trim the nozzle but a good rule of thumb is to cut at a 45-degree angle and create a 5-6mm hole in the end of the tube, which can be enlarged if a wider bead is required.

Trim the nozzle of the silicone sealant tube at a slight and angle and do not be tempted to make the aperture too large

4 - Applying silicone sealant to the shower tray

Apply the silicone sealant to the inner corner of the shower tray. Use gentle pressure to the trigger of the application gun and work towards the front of the shower tray in one continuous, smooth action to ensure application of a uniform silicone bead.

Applying silicone sealant in a continuous bead from the back corner of the shower tray to the front

5 - Be careful

Do not apply too much sealant as excessive amounts can be difficult and messy to remove.  More sealant can be applied prior to smoothing if required

6 - Make sure there are no gaps in the sealant bead

Ensure the bead of silicone sealant is continuous and thick enough to fully cover the gap between the shower tray and the tiles. If any visible gaps remain, carefully add a little more sealant to these areas.

A correctly applied bead of sealant to a shower tray with no gaps or bubbles prior to smoothing and finishing

7 - Clean the sealant application nozzle

Once you have finished each line of sealant, release the pressure from the application gun. Wipe away excess sealant from the nozzle and replace the cap. Residual pressure can remain in the tube causing silicone sealant to leak from the nozzle so take care!

8 - Achieving a perfect silicone sealant bead

Starting from the point the silicone was first applied, place the silicone sealant smoothing tool against the shower tray and tiles. Apply gentle but even pressure and draw the tool along the length of the shower tray, remove excess silicone and leave a neat bead as you go. 

A Fugi silicone sealant finishing tool creates a neat bead of silicon sealant around the perimeter of the shower tray

9 - Take care not to tear the new silicone sealant

Once a smooth, uniform bead has been achieved around the shower tray, do not be tempted to keep smoothing the silicone as it will start to tear, look untidy and may not adhere correctly.

10 - Allow the silicone sealant to dry fully

Allow to cure fully according to the manufacturer’s instructions. Usually, fresh silicone should be left to dry or cure for a minimum of 24 hours, although this depends on the brand and type of sealant.

A perfectly straight and neat fresh bead of silicone sealant applied around the edges of a shower tray to prevent water leaks

Resealing a shower enclosure

Whether you are resealing the shower enclosure in the bathroom at home or you are a contractor planning on sealing showers for a large development, the best advice we can give you is:

  • Remove old sealant – Use a sealant remover to dissolve the existing sealant, or, carefully scrape at it with a plastic or metal blade.
  • Clean and dry – Use warm water containing a mild detergent to thoroughly remove grime and residue from the area and then use paper towels or a hairdryer to speed up the drying process.
  • Make it neat – A sealant application tool, such as the Fugi by Cramer, will help you to achieve a neat and even bead of silicone sealant
  • Follow the manufacturer’s instructions – As a rule of thumb shower doors and enclosures should only be sealed around the outside at the bases and on the inside and outside of the vertical profiles where they meet the tiled walls.  Sealing around the base on the inside will often cause a shower enclosure to leak.  Carefully read the manufacturers sealing instructions before applying silicone sealant.
  • Seal that shower – Follow our shower tray sealing tips above for hassle-free shower sealing with a smooth, neat finish.

Some tips on sealing a bath

We know that not everyone has the luxury of a freestanding bath and that many modern bathroom designs will incorporate over-bath showers that also require sealing.  When sealing a bath, follow the preparation advice above but remember that there is one crucial extra step you will need to take before reaching for the silicone sealant.

  • Make sure the bath is filled with water prior to applying the sealant
  • The water in the bath acts as a weight (most baths settle slightly when filled due to the movement in flooring) and ensures that the silicone sealant will not stretch or tear when the tub is filled at bath time and the weight of a human is added.

Shower sealing, installation and more

Room H2O appreciates that DIY is not everyone’s cup of tea and there are some jobs you would rather leave to the professionals. With that in mind, we offer a full range of specialist services from bathroom installation services in Dorset to made to measure shower enclosure survey and installation services throughout the South East. Should you require more information about our shower sealing and bathroom fitting services, do not hesitate to get in touch

Contact our Dorset bathroom shower design team on 01929 551963 or wareham@roomh2o.co.uk

Contact our Surrey bathroom shower design team on 0208 393 3888 or epsom@roomh2o.co.uk

Here we can see the fresh silicone that has been applied to the shower tray and smoothed to a neat finish with the help of a sealant application tool
The right tools for the job