Shower Tray Leaking — How to Reseal
Do not use the shower for 24 hours after applying new silicone sealant — the silicone must fully cure before it is waterproof.
A leaking shower tray is one of the most common bathroom DIY repairs. In the majority of cases the cause is perished or cracked silicone sealant around the tray edge or door frame rather than a cracked tray. Resealing with sanitary silicone is a straightforward job that takes a couple of hours.
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Remove all the old silicone from the joint. Use a silicone remover tool (a plastic blade, £2 from DIY stores) and silicone dissolver liquid to soften stubborn sections. Take time to remove every trace — new silicone will not bond to old silicone.
Clean the joint surfaces thoroughly with methylated spirits or isopropyl alcohol on a cloth. The surfaces must be completely dry and free of soap scum, mould, or grease before applying new silicone.
Apply masking tape to both sides of the joint — along the tray edge and along the tiles or wall — leaving the joint gap exposed. This gives a clean, straight finish.
Load a cartridge of sanitary silicone (not standard frame sealant — use bathroom silicone with mould inhibitor, e.g. Dow Corning 785 or Everbuild 500) into a silicone gun.
Apply a continuous bead of silicone into the joint, moving the gun smoothly and consistently along the full length.
Wet your fingertip with clean water and run it firmly along the bead in one smooth stroke to press it into the joint and create a concave profile. Work quickly — silicone starts to skin within minutes.
Remove the masking tape immediately while the silicone is still wet, pulling it back at an angle. Leave undisturbed for 24 hours before using the shower.
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