Maintenance
When to replace silicone sealant (and why it matters)
The silicone sealant around your sink, shower screen, bathtub and countertops does a quiet but important job — keeping water out of the joints where surfaces meet. When it blackens, peels or cracks, it’s not just unsightly; it’s failing at that job, letting water seep behind and feed mould and damage. This guide covers when to replace silicone sealant and why it matters.
Key takeaways
- Replace sealant when it’s mouldy, cracked, peeling or lifting.
- Failing sealant lets water behind sinks, screens and worktops.
- It’s a small, cheap job that prevents bigger water damage.
- Proper removal and a clean, dry surface make the new bead last.
What silicone sealant does
Silicone seals the gaps at edges and joints — where the shower screen meets the tiles, around the sink and basin, along the countertop backsplash, and at the base of fittings. These are exactly the spots where water collects and would otherwise get behind the surface. Good sealant keeps that water out; failed sealant invites it in.
Signs it needs replacing
- Black mould ingrained in the silicone that won’t clean off.
- Peeling or lifting edges where it’s no longer bonded.
- Cracks or gaps that expose the joint.
- Discolouration and hardening as it perishes with age.
- Water getting behind a sink, screen or counter.
Why you shouldn’t just leave it
Failed silicone lets water into joints and behind surfaces, where it feeds mould, damages cabinetry and can contribute to bigger moisture problems over time. Replacing perished sealant is a small, inexpensive job that prevents costlier damage — and it instantly freshens up a tired-looking bathroom or kitchen.
Cleaning vs replacing
If the silicone is intact and just lightly dirty, cleaning may be enough. But once it’s mouldy through, peeling or cracked, cleaning won’t save it — it needs raking out and re-applying with fresh silicone. Persistent mould that returns despite cleaning is a sign the sealant (or the grout) has failed. If damp problems go deeper than the joints, it may point to waterproofing that needs attention.
Frequently asked questions
Can I just clean mouldy silicone? If it’s intact, yes; once mould is ingrained or it’s peeling, it needs replacing.
How often should silicone be replaced? When it shows signs of failing — mould, peeling, cracks — which varies with use and ventilation.
Is failed silicone a waterproofing problem? It’s surface-level, but leaving it lets water in; deeper or recurring damp may point to the membrane beneath.
Does new silicone stop the mould coming back? Combined with good ventilation, yes — fresh sealant with mould inhibitor resists regrowth.
The bottom line
Blackened, peeling or cracked silicone has failed at keeping water out — replace it promptly. It’s a small job that prevents mould and moisture damage and refreshes the look.
Silicone or damp issues? See our waterproofing service, and read about grout cleaning vs regrouting. Get a free assessment today.
