A leaking shower is more than just an annoyance. Left undetected, a shower leak can cause significant damage to floor structures, ceilings below, and surrounding walls — leading to rot, mould, and in serious cases, structural damage.

Where Do Shower Leaks Come From?

1. Failed Silicone Seals

The silicone seal where the shower tray, screen, or enclosure meets the wall or floor is one of the most common leak points. Silicone degrades over time, shrinks, discolours, and eventually loses its waterproof seal. Mould growing on the silicone is usually a sign it has already begun to fail.

Fix: Strip out all old silicone, clean the surface thoroughly, and apply fresh sanitary silicone. This is one of the few shower repairs a competent DIYer can tackle.

2. Failed Tile Grout

In a tiled shower enclosure, the grout between tiles is not waterproof in the same way that the tiles themselves are. Over time, grout cracks, crumbles, or is simply applied too thinly and allows water to penetrate behind the tiles, saturating the wall substrate.

Fix: Rake out old grout, ensure the substrate behind is dry, and regrout. If water has been getting behind tiles for some time, the tiles may need to come off to allow the wall to dry and the substrate to be treated or replaced before retiling.

3. Shower Tray Leaks

Shower trays can leak from the waste fitting, from cracks in the tray itself, or from the seal between the tray and the wall. Acrylic trays can flex under load, which over time breaks the seal at the edges.

Fix: Check and reseal the waste fitting, reseal the tray edges, and check the tray for hairline cracks. A cracked or heavily flexing tray usually needs replacing.

4. Shower Screen or Door Seals

The rubber seals on shower screens and door enclosures deteriorate with age and use. Water can track through gaps in the frame or through worn seals onto the bathroom floor, then seep through floor gaps or around the tray seal.

Fix: Replacement seals are available for most standard enclosures and are a straightforward repair. If the frame itself is damaged or corroded, a new enclosure may be more cost-effective.

5. Mixer Valve and Pipework

Leaks from within the wall — from the mixer valve body, from pipe joints behind the tiles, or from the flexible hose connections — can be harder to detect because the water appears elsewhere. Signs include persistent damp on the wall surface, a ceiling stain below the shower, or unusually high water consumption.

Fix: This type of leak requires a plumber to access the pipework, which usually means removing tiles. It's not a DIY job.

6. Inadequate Tanking

In a shower enclosure, the wall and floor substrate must be waterproofed (tanked) before tiling. If this wasn't done properly during installation, water slowly works its way into the substrate over time. The fix is usually to strip the shower enclosure back to the substrate, dry everything out, apply a proper tanking system, and reboard and retile.

If you have a ground floor shower and notice damp appearing on the ceiling below, or a musty smell in the room adjacent, act quickly. Water tracking through floor structures causes rot and can be expensive to remedy if left.

When to Call a Professional

• Any leak involving pipework within the wall
• Damp appearing on adjacent walls or ceilings below
• Tiles that are hollow, loose, or moving
• A shower tray that flexes significantly underfoot
• Any sign of structural dampness or rot in floor timbers

Wittick Building Tip: Wittick Building handles full shower refurbishments, wetroom installations, and shower leak investigations. If you're not sure where a leak is coming from, we can diagnose it and give you honest advice on the most cost-effective fix.