Renewing bathroom silicone joints

Difficulty: Medium · Time: approx. 45 minutes

An old silicone joint that's yellowed, cracked or mouldy doesn't just look bad – eventually it lets water through. Renewing it is very doable, but it takes care and patience when smoothing.

Most of it is preparation: removing the old silicone completely and working cleanly. Allow drying time – the new joint should cure for 24 hours before it gets wet.

What you'll need

  • Utility knife or joint scraper
  • Sanitary silicone (mould-resistant) + a caulking gun
  • Masking tape
  • Smoothing agent or a little soapy water
  • Cloth + a joint smoother (or a clean finger)

Step by step

  1. 1

    Remove the old silicone

    Cut into the old joint on both sides with the knife and peel it off. Remove residue with the scraper – the surface must be completely clean, or the new silicone won't hold.

  2. 2

    Clean and dry

    Clean the joint thoroughly, remove any mould residue, then let it dry completely. Moisture is the most common reason joints go mouldy.

  3. 3

    Mask off

    Stick a strip of masking tape on each side of the joint, evenly spaced. This gives a clean edge.

  4. 4

    Apply the silicone

    Cut the cartridge tip at an angle to the right size and press silicone into the joint in one even pass – better slightly too much than too little.

  5. 5

    Smooth and pull the tape

    Wet the joint with smoothing agent/soapy water and draw it smooth in one pass with a smoother or finger. Then pull off the tape IMMEDIATELY while the silicone is still wet. Cure for 24 hours.

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Frequently asked questions

How long does the new joint need to dry?
Usually 24 hours before it gets wet again. The exact time is on the cartridge – thick joints take longer.
Why won't my joint go smooth?
Usually the smoothing agent is missing: without a wetted surface the silicone sticks to your finger and tears. Use soapy water or a dedicated agent and work in ONE pass.