How to Seal a Bath

By George

21st Jan 2018

7 mins read

DIY & Technical

A rite of passage for any budding DIYer, sealing a bath is a relatively easy job that will provide an essential finishing touch for any new bathtub.

back to wall curved modern bath

Applying sealant to a new tub is often one of the final things to tick off when completing a renovation.

This simple strip of silicone sealant works to prevent any water from escaping down the back and sides of your bath.

Without it, the gradual build-up of water could lead to costly and dangerous problems such as flooding, rotten floorboards, and considerable mould.

Already have a bath installed? Replacing old or mouldy sealant can provide your bathroom with a fresh boost, while also reassuring you that your tub is still watertight.

With this in mind, we put together the following guide to teach you how to seal a bath.

Before we begin, however, you’ll need to get your hands on the following items:

  • Work Gloves - A good pair of work gloves will keep your hands safe throughout the process. For this particular job, we recommend choosing a pair of strong nitrile gloves.
  • Masking Tape - Any masking tape will do, so long as it has good enough adhesion to stick to your tub.
  • A Sealant Gun - Don’t attempt this without one! Sealant guns, such as the Bond It Sealant Gun pictured below, are used to give you precise control over how much sealant you apply.
  • A Quality Silicone Sealant - Be sure to go for a reputable brand, preferably one with anti-mould properties to give you long term protection. Scrimping on this could lead to you having to re-do the whole job!
  • A Seal Smoother (Optional) - Leave it to the professionals to perfect their lines just using a finger! A good seal smoother will help you easily wipe away the excess sealant and create that impeccable finish.
  • A Safety Knife - You’ll need this to open your sealant tube.
  • Paper Towels/Kitchen Roll - Great for collecting any excess silicone when you come to smoothing your sealant.

Please note: This guide is for those who have recently installed a brand new bath. If you’re wanting to replace an old bath’s sealant, click here to skip ahead to our ‘How to Remove Bath Sealant’ section first.

How to Seal a Bath Properly In 7 Simple Steps

This can be quite daunting for first-timers - but we’ll lead you through how to apply bathroom sealant to a high standard in our safe and simple steps!

  1. Keep Things Clean - Ignore this step at your peril! With a brand new tub, you’d be forgiven for thinking there’s no need to clean around the edges. However, failing to make sure your bath is completely clean and dry before starting could result in problems - such as black mould growth and imperfect lines. Be sure to check the wall you’re sealing to is clean and dry too!
  2. Time for Tape - Now it’s time to apply two lines of masking tape. One along the edges of the bath, and one along the wall/tiles - leaving only the gap that you wish to seal visible. This will ensure that any excess silicone can be easily peeled away, while also giving you a clear guide to where you’re applying the sealant.
  3. Fill Your Bath - Similarly to the first step, we highly recommend taking this precautionary measure to prevent any nasty surprises further down the line. The additional weight of a full bath can slightly increase the size of the gap you are about to fill. If you fail to do this, your sealant could crack or peel away from the wall when you come to take your first bath.
  4. Set Up Your Sealant Gun - Grab those work gloves - you’ll need to keep your hands protected from here on out. This stuff is a nightmare to get off! Once you’re ready, take your safety knife and - after removing the nozzle - carefully cut off the tip of your silicone sealant. Then carefully insert the canister into your sealant gun. Attach the nozzle and you’re good to go!
  5. Apply Your Sealant - If you’ve never been taught how to apply bathroom sealant this can seem a little nervewracking. However, it is relatively straightforward if you’ve followed all the other steps. Starting at the corner of one edge, get really close to the gap and gently squeeze the trigger carefully until the silicone begins to flow. Slowly follow the line you’ve marked with tape in one careful motion - being cautious not to go over any silicone you’ve already put down.
  6. The Finishing Touches - Here’s the magic part. If you’re applying sealant for the first time, you may be concerned to find that you’ve created uneven, bobbly lines. This is completely normal - silicone won’t come out picture perfect regardless of how gently you pull the trigger of your sealant gun. Take your seal smoother (or a wet fingertip if you’re feeling confident!) and - at an angle - glide along your lines of sealant to smooth them. Collect any excess silicone using paper towels or kitchen roll.
  7. Job Done! - It’s as simple as that! Be sure not to use your bath for 24hrs to allow it to properly cure. After this, just peel away the tape to reveal a perfectly sealed tub!

How to Remove Bath Sealant

If you’re sticking with your old bath - replacing the old sealant can make a huge impact on its appearance. Luckily, removing this is quite simple too.

Start by protecting the edge of your bath closest to the sealant with masking tape. Next, take a safety knife and cut along your lines of sealant - pulling it away and gently scraping any stubborn bits off with a flat edged tool. Try rubbing away any leftover residue by hand.

Struggling to remove every last bit? We heartily recommend opting for a specialised sealant removal tool, such as this one from Tile Rite. White spirit can help loosen particularly troublesome debris too, but be careful and use it sparingly.

Successfully sealed your tub? Stick with us on the Victorian Plumbing blog for more ‘How to’s’ for your bathroom inspiration. Still haven't picked out a bath? Take a look at our complete collection of quality baths.



George is one of our interior experts. He loves to write about the latest bathroom trends and he's a dab hand with bathroom DIY too.

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