Remove Mould in the Bathroom: Clean & Replace Joints

July 5, 2019
  1. Clean joints
  2. Remove mould
  3. Replace joints

Through daily use the bathroom is exposed to constant stress. When taking hot showers, the humidity created attacks the walls of the room, which can cause dangerous mould growth if ventilation is insufficient. Mould loves warm, humid conditions and spreads not only on the walls but also in the tile joints or on silicone seals. Tile joints protect gaps from water penetration and are naturally the most exposed in the bathroom. The silicone becomes brittle and cracked over time - providing a breeding ground for mould. 

You can recognise mould by the black discolouration. If this is the case, you should replace the joints. If you are handy, you can do this yourself. In the case of smaller stains, you can remove the mould yourself with simple tricks. If there is only yellowing, it is not necessary to replace or clean the mould. The yellowed grout can be easily cleaned with a proven household remedy.

Clean joints

This is how it works:

  1. Use a special cleaning agent and an old toothbrush for scrubbing. A proven home remedy is washing powder or baking soda
  2. Mix the baking soda and water together to make a paste and rub it onto the joints with the toothbrush.
  3. Leave the mixture to act for approx. 1 hour
  4. Rinse the joints with water. Done!

Houzy Hint


While cleaning check whether cracks have already formed in the joint. If black mould is also growing in it, you should think about replacing the putty joints. Below we explain how you can replace the joints yourself with a little manual skill.

Remove mould

If you have discovered black stains, you should act - because mould is harmful to health and destroys the fabric of the building. You can treat small stains yourself before you replace the putty joints or call in a professional.

This is how it works:

  1. Before you start, open the windows if possible and close the doors to other rooms - because fumes are produced when cleaning.
  2. Put on work gloves or rubber gloves.
  3. Dab 70-80% alcohol (ethanol/brandy) as a mould remover onto the affected area with a sponge or rag
  4. Let it act briefly and then wipe dry with paper.
  5. Remove any remaining stains with a bleaching agent (hydrogen peroxide). Follow the manufacturer's instructions for use.
  6. Consult a professional in case of large-scale or recurring mould infestation.

Replace joints

This is how it works:

  1. Clean the surfaces around the joint and remove it with a joint scraper and cutter knife. Close the drains beforehand so that no silicone gets into the waste water.
  2. If not everything can be removed completely, use silicone remover according to the instructions.
  3. Tape the edges with paint paper if necessary.
  4. Fill the joint evenly using a silicone gun. The joint width should be 1 to 2 millimetres wider than the gap, as silicone shrinks somewhat over the years.
  5. Smooth the joint with a joint smoother while the silicone is still wet.
  6. Remove any silicone splashes on the surrounding surfaces and allow the fresh joints to dry for 24 hours.

Would you like to receive more DIY tips and useful information about your own home? With Houzy, you can easily digitally record your home, check renovation needs, plan maintenance work, find qualified craftsmen and more. Try Houzy for free!

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