Domakihub How to Seal a Leaking Shower Tray and Stop Water Damage
Replace failed silicone, protect your floors, and keep moisture out for good.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
A leaking shower tray is one of the most common — and most damaging — problems in Greek homes, holiday rentals, and hotel rooms. Left unchecked, water seeps through the joint between tray and wall tiles, rotting the substrate and eventually staining the ceiling of the room below. The video above walks you through the visual process; this guide breaks it into clear, ordered steps so you can tackle the repair with confidence.
Why Shower Tray Joints Fail
Shower trays move slightly every time weight is applied. Over months and years this micro-movement cracks the original silicone sealant, opening gaps that are invisible until damp patches or mould appear on the wall or ceiling. In Greece the combination of hard water minerals and high summer humidity accelerates the breakdown.
Acrylic and stone-resin trays are especially prone to flexing because they are lightweight. Even a well-installed tray can start leaking within three to five years if a low-grade sealant was used during installation.
Choosing the Right Sealant
Use a sanitary-grade, fungicide-treated silicone that is specifically labelled for wet zones. Neutral-cure silicone sticks better to acrylic, fibreglass, and enamel than acetoxy (acetic-acid) types, which can attack some surfaces. Match the colour to your grout or choose bright white — it reads cleaner under bright bathroom light.
Avoid general-purpose silicones sold for windows or glazing; they lack the mould inhibitors your bathroom needs. Budget for 150–200 ml per standard shower tray perimeter, plus a cartridge gun if you do not already own one.
How to Reseal a Leaking Shower Tray: 5 Steps
- 1
Remove all old sealant
Use a Stanley knife or dedicated silicone removal tool to slice along both sides of the existing bead and peel it away in strips. Work carefully so you do not score the tray surface or tile glaze. Follow up with a silicone-dissolving spray or white spirit on a rag to lift any residue, then wipe dry.
- 2
Clean and degrease the joint
Mould spores and soap scum left in the joint will prevent adhesion. Spray the channel with a dilute bleach solution (1:10), let it sit for ten minutes, scrub with an old toothbrush, and rinse thoroughly. Allow the joint to dry completely — at least two hours in a ventilated room, longer in humid weather. Do not rush this step; moisture trapped under fresh silicone is the main reason re-sealing fails.
- 3
Tape both sides of the joint
Apply masking tape in two straight lines, one on the tile and one on the tray, leaving only the joint gap exposed. This creates clean, sharp edges and saves significant clean-up time. Press the tape firmly so silicone cannot bleed underneath it.
- 4
Apply the silicone bead
Cut the nozzle at a 45-degree angle to match the width of your joint — typically 4–6 mm. Hold the gun at a consistent angle and move it at a steady pace along the full length of each side without stopping. One continuous pass produces a neater result than multiple short strokes. Once complete, wet your finger or a sealant profiling tool with soapy water and smooth the bead in a single motion to push it firmly into the joint.
- 5
Remove the tape and cure
Pull the masking tape away immediately — before the silicone skins over — by lifting at a low angle. This prevents the bead from tearing. Leave the shower unused for a minimum of 24 hours, or ideally 48 hours, to allow full cure. Most sanitary silicones are water-resistant within an hour on the surface but need the full curing period to achieve waterproof strength throughout the bead.
Rather have a pro handle it?
Get a vetted plumbing pro in your city — one number, booked in EN/EL/DE.
FAQ
- How do I know if my shower tray is leaking through the sealant or through the waste fitting?
- Fill the tray with enough water to cover the waste cover, then block the drain with a cloth or rubber stopper. Wait 30 minutes. If the water level drops, the leak is at the waste fitting, not the perimeter sealant — and you will need to access the trap from below or remove the waste flange. If the level holds steady but you still see damp patches at the base of the wall, the perimeter joint is the culprit.
- Can I apply new silicone over the old bead to save time?
- No. Fresh silicone bonds to clean, dry surfaces — not to old silicone, soap scum, or mould. Applying a new bead on top of a failed one gives you two layers of sealant that will both fail quickly, and the joint will be harder to clean properly next time. Full removal is the only approach that produces a lasting result.
- How long should a properly sealed shower tray last before it needs resealing?
- With a good-quality sanitary silicone and correct surface preparation, a joint should remain watertight for five to eight years in normal domestic use. Holiday rentals and hotel bathrooms see heavier traffic and may need inspection every two to three years. Annual visual checks — looking for discolouration, cracking, or lifting edges — let you catch and fix minor issues before they cause structural water damage.