Is Your Shower Leaking? It Could Be the Silicone

A leaking shower is one of the most common — and most damaging — problems New Zealand homeowners face. What many don’t realise is that the culprit is often not the waterproofing membrane or the tiles themselves, but the silicone sealant around the edges.

What Does Silicone Do in a Shower?

Silicone sealant fills the flexible joints in a shower — the corners, the junction between tiles and the shower tray, and around fittings like taps and drains. Unlike grout, silicone is designed to flex with the natural movement of a building without cracking.

When silicone fails, water gets in. And because shower walls and floors are constantly wet, that water has nowhere to go except into the wall cavity or subfloor.

Signs Your Silicone Needs Replacing

• Mould that keeps coming back — Black mould on silicone is almost impossible to permanently remove with cleaning products. The silicone itself becomes colonised.
• Silicone pulling away from the wall or tray — You can see gaps or the silicone is lifting at the edges.
• Cracked or brittle silicone — Old silicone hardens and loses its flexibility, leading to cracks.
• Discolouration that won't shift — Yellow or brown silicone is beyond cleaning and should be replaced.
• Water appearing in unexpected places — Damp patches on walls, ceilings below showers, or on adjacent floors.

Why DIY Silicone Replacement Often Fails

It looks straightforward — cut out the old silicone, apply new. But a poor silicone job can actually make things worse. Common DIY mistakes include:

• Not removing all of the old silicone, causing the new sealant to fail to adhere
• Applying silicone to a damp surface
• Using the wrong type of silicone (not all silicone is mould-resistant or suitable for wet areas)
• Poor finishing, leaving gaps or an uneven bead

Professional Silicone Replacement

The Grout Guy’s silicone replacement service ensures every bit of old sealant is removed, the surface is properly prepared and dried, and a premium mould-resistant silicone is applied with a clean, professional finish.

Don’t let a failing sealant turn into a costly water damage repair. Contact us for a free assessment.