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Sealing ahoy!

How to seal a bath: Step-by-step instructions

If the sealant around your bathtub is starting to lift or go mouldy, it’s time to replace it! Knowing how to seal a bath and sink will help save a lot of time and money! If left untreated, moisture will seep into your walls making the problem even worse. So, don’t wait! Our bathroom sealing tips will have you re-sealing your tub in no time!

Tools for re-caulking a tub

Replacing the seal around your bath is easy with the right tools. Doing it right the first time ensures your home is protected for years to come. Here are the tools you need for replacing sealant around a bathtub.

To complete the job, you will need the following:

  • Box cutter or straight blade: To remove the old seal
  • Tweezers: To remove any small pieces that are stuck
  • Vacuum cleaner: To clean up fast
  • Methylated spirit and cloth: To clean the surface of your bathtub before reapplication
  • Bleach solution: For removing mould or mildew
  • Painter’s tape: For ensuring new straight lines
  • Cartridge gun: For ease of application 
  • Sealant: Preferably one that’s waterproof and formulated for the bathroom
  • A smoother tool: For smoothing the line of sealant after application
  • Gloves: Optional

The perfect sealant for sealing a bathtub

With so many choices on the market, it can be difficult to tell what tools are best for the job. Picking the right sealant is important for meeting the needs of your home, so here are some things to consider to help you choose.

UniBond Anti-Mould Sealant has been specifically formulated to create a flexible, long-lasting seal that is resistant to mould and mildew. With regular cleaning, this sealant will last for years to come.

If mould is a big issue in your home, then we recommend our star product, Unibond Triple Protection Anti-Mould Sealant. It is a strong, waterproof, and durable sealant which is ideal for all your sanitary sealing needs in warm and humid environments such as bathrooms and kitchens

If you’re pressed for time and need a quick and reliable fix, turn to Unibond Speed Seal Sealant. This sealant boasts the fastest sealing time, and allows for water contact after just an hour of drying.

How to seal a bathtub

Removing old sealant from tubs

Removing the old materials is the first step in creating a new seal. Here’s how to remove old sealant from the bathtub.

  1. Use the box cutter to remove existing sealant. Run the razor flat against the old sealant line following the moulding around the bathtub. Take care not to scratch the surfaces. 
  2. Go back over the space with tweezers to remove any small pieces of remaining sealant. 
  3. Using methylated spirit and a cloth, wipe down the area to make sure that all the pieces have been removed. 
  4. Use the vacuum cleaner to remove any remaining pieces. Make sure you have completely removed all of the sealant around the bathtub.
  5. Make sure to remove and clean all mould or mildew with a mould remover.


  1. Double check that your workspace is clean and that all substances are removed from the application area. Apply masking tape in two straight lines around the grout line. This will keep your borders straight and neat. 
  2. When sealing around a bath, fill it with water before you begin applying the sealant and leave full until the sealant has completely cured.
  3. Cut the tip off the cartridge just above the screw head. Trim the nozzle at a 45-degree angle. Make sure to only cut enough to achieve the bead size you need, then screw on the nozzle.
  4. Load UniBond Anti-Mould Sealant or alternative UniBond sealant into the gun. 
  5. Place the nozzle at your starting point. Apply consistent pressure to the gun trigger, as you gently apply a smooth line of sealant around the tub. 
  6. Once you have finished sealing around the bathtub, run the smoothing tool along the seam to smooth out the grout. 
  7. Remove the tape before the sealant dries. 
  8. Using a wet rag, wipe away excess sealant before it has a chance to dry. Check the package instructions, but a good rule of thumb is to let it sit for at least 48 hours before using the tub again.

How to remove difficult silicone sealant

Once the drying time has passed, it’s safe to use your sparkling new bathtub! If your application was a little messy and grout made it into unwanted places, no problem! Dip a rag in methylated spirit and give it a wipe to loosen the material, and use a plastic scraper to work it off.

How to seal your bath using UniBond sealant - just follow our easy instructions!

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