Wipe out mould

For the perfect bathroom: How to clean silicone sealant

A build-up of black mould on silicone sealant can make our bathrooms look very unsightly. Here’s how to clean it off.

Why is silicone sealant cleanup necessary?

Silicone sealant is mostly found where sinks, bathtubs and shower trays meet a tiled wall, to prevent water from seeping behind them. The warm, humid environment found in bathrooms is the perfect place for mould to grow – including on silicone sealant.

If you leave the mould to develop, eventually you will have to replace the sealant, which can be a time-consuming project. Fortunately, learning how to clean bathroom sealant is simple and easy. 

Cleaning silicone sealant: mould and mildew remover

The best solution is a specialist bathroom mould and mildew remover, as this product has been specifically formulated to kill the mould spores and will therefore provide the longest protection. These are available from most DIY stores and supermarkets. Check the product’s instructions and use as directed.

You might see vinegar, a combination of baking soda and vinegar or bleach recommended as cleaning solutions for silicone sealant elsewhere. However, although these products may work to some degree, they do not kill the spores and have the potential to damage the sealant bead. We recommend that you only use a specialist bathroom mould and mildew remover or, if that is not effective, replace the sealant altogether. 

Use the right sealant

The best way to avoid mould growth in your bathroom is by using an anti-mould sealant in the first place, or to replace sealant where you are unable to remove mould growth. UniBond’s Sanitary Anti-Mould Sealant is a waterproof and flexible silicone sealant specially formulated to prevent mould growth in humid environments such as kitchens and bathrooms. Long-lasting and easy to use, it is 'touch dry' within just 20 minutes and fully dry within 24 hours.

Even better, UniBond Kitchen & Bathroom Triple Protect Sealant contains an enhanced fungicide system which repels, kills and prevents mould to keep your baths, showers, sinks, tiled areas, toilets and worktops in pristine condition. 

How to clean silicone sealant: Remove and replace sealant

In cases where the mould has set too deeply into your sealant, it will need to be removed and replaced. To do so, follow these simple steps:

  1. Remove. First use the UniBond 2in1 Sealant Remover and Smoother Tool to remove as much of the existing sealant as possible. Then use the UniBond Silicone Sealant Remover to remove residues.
  2. Clean. After removing the old sealant, use a cloth moistened with white spirit to remove any dirt that might have accumulated around the joint. 
  3. Prepare. Cut the tip of the cartridge above the screw thread and trim the nozzle to size. Don’t worry if you cut too small at first – you can always make the aperture larger. Load the cartridge into a standard cartridge gun
  4. Seal. Place the tip of the dispenser at one end of the joint you are sealing and gently but firmly squeeze the trigger, working the tip along the joint in a steady, continuous motion to achieve an even bead of sealant.
  5. Finish. As soon as the sealant has been applied, use UniBond’s Sealant Smoother Tool to compact and smooth it into the joint, achieving a professional-looking finish. Remove excess sealant immediately using a cloth dampened with white spirit. Check the product’s instructions to see how long it needs to cure before allowing water contact.