Bathroom · DIY guide
How to reseal silicone around a bath or shower
Mouldy, lifting silicone is the fastest way to make an otherwise fine bathroom look neglected — and it is genuinely a two-hour job. The trick is almost entirely in the removal and the masking, not the piping.
Legal to DIY in Victoria
What you need
- Silicone remover gel and a plastic scraper or Stanley knife
- Neutral-cure sanitary silicone (mould resistant) — not acetic cure on stone
- Caulking gun, masking tape, methylated spirits
- Paper towel and a small container of soapy water
Step by step
Cut the old bead out completely
Score both edges with a sharp blade and peel the bead away in one piece if you can. Then use silicone remover gel on the residue and scrape it back. New silicone will not stick to old silicone, so anything left behind becomes a leak path.
Degrease and dry
Wipe the joint with methylated spirits and let it dry fully. Any soap film, mould spray residue or moisture stops adhesion. If the joint has been wet, give it a few hours.
Mask both sides
Run masking tape either side of the joint, about 3mm back from where you want the silicone edge. This is what separates a professional-looking bead from an obvious DIY one.
Lay the bead in one pass
Cut the nozzle at 45 degrees, opening slightly smaller than the joint. Push — do not pull — the gun along the joint at steady pressure, finishing the full run in one movement if possible.
Tool it, then pull the tape immediately
Dip a finger in soapy water and draw it along the bead once, firmly. Pull the masking tape off straight away while the silicone is wet, at a shallow angle away from the joint. Waiting until it skins ruins the edge.
Leave it alone for 24 hours
No showers, no water on the joint. Neutral-cure silicone needs a full day. Using the shower that night is the most common reason a fresh bead fails within a month.
Common mistakes
- Siliconing over old silicone
- Using acetic-cure (vinegar smell) silicone on natural stone — it etches it
- Cutting the nozzle too big and trying to tool away the excess
- Leaving the masking tape on until the silicone skins
- Getting the joint wet before it has cured
When to stop and call someone
If the silicone keeps failing in the same place, or the joint is more than about 8mm wide, something is moving underneath. A wide, recurring gap between bath and wall usually means the bath is not properly supported — silicone is not the fix.