How to Fix Mouldy Shower Silicone Seals | Step-by-Step DIY Guide, by ecologicaltime on YouTube. 13 min 57 s.
- Video length
- 13 min 57 s
- Time to do it
- 2 hours plus 24 hours curing
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Run a sharp scraper or silicone removal tool along both edges of the old bead to cut it free. Work slowly and keep the blade flat so you do not gouge the tray or tiles.
Pull the loosened silicone away in one long strip. Pick out any stubborn pieces with the corner of the scraper, then wipe the joint with a cloth.
Spray the mouldy joint with mould cleaner or neat white vinegar and leave it 15 to 20 minutes. Wipe it clean, then let the area dry completely.
Wipe the joint with methylated spirits on a cloth to strip grease and soap residue. Silicone will not stick to a dirty or damp surface.
Press masking tape along the tile and tray edges to leave a clean gap about 6 to 8 mm wide. Rub the tape down firmly so sealant cannot creep under it.
Load the cartridge into the caulking gun and cut the nozzle at a 45 degree angle, roughly the width of the gap. Pierce the inner seal first.
Push the bead along the joint in one steady pass, keeping the nozzle tip in the silicone. Overlap your start point rather than stopping and restarting.
Smooth the bead with a wet finger or silicone smoothing tool in one stroke. Peel the masking tape off straight away while the silicone is still wet.
Leave the new seal undisturbed for at least 24 hours before showering. Check the instructions on your cartridge for the exact curing time.
Tips and common mistakes
Never apply new silicone over old sealant, because the new bead will peel off within weeks.
Fill the bath with water before sealing a bathtub joint so the weight pulls the gap open and the bead does not split later.
Keep the bathroom well ventilated while using mould spray and wear gloves and safety glasses.
Buy a bathroom-rated, mould resistant silicone rather than a general purpose one for wet areas.
Questions
Can I just clean the black mould instead of replacing the silicone?
Surface mould comes off with vinegar or bleach, but mould that has grown inside the silicone will keep coming back. Once the bead is black through the middle, replacement is the only lasting fix.
How long before I can use the shower again?
Most bathroom silicones need around 24 hours to cure and some need 48. Check your cartridge and keep the area dry until then.
Why did my last silicone bead go mouldy so fast?
Usually the surface was damp or greasy when you applied it, or the sealant was not bathroom grade. Cleaning with methylated spirits and buying a mould resistant product makes a big difference.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
