Why sealant goes mouldy
Mould grows where the joint stays damp and warm, feeding on soap and skin residue. Poor ventilation and joints that never dry make it worse. Once mould gets into the silicone, it’s under the surface.
Can you clean it?
Surface marks sometimes clean off with a mould remover. If the black is still there after cleaning, it’s inside the silicone and won’t come out.
Resealing properly
Sealing over old silicone doesn’t work. The new bead won’t bond, and mould underneath keeps growing. The old sealant has to be cut out fully, the joint cleaned, treated and dried, and new sanitary silicone applied. For a bath, filling it with water before sealing stops the bead tearing the first time it’s used. See bath and shower resealing.
Stopping it coming back
- Run the extractor fan during and after a shower or bath.
- Wipe the sealant joints dry after use.
- Leave the shower door or curtain open to air.
- Clean the joints regularly with a mild cleaner.
When it’s more than mould
If sealant has split and water has got behind the bath or tray, you may see stains on the ceiling below or loose tiles. Reseal quickly to limit the damage.
Every job is different. Send us a photo and we’ll tell you what we’d recommend for your bath, sink or surface.
