Diagnosing a shower leak, step by step.
Most 'shower leaks' are one of four things: failed silicone, cracked grout, a compromised hob joint or a failed membrane. Rebuilding without diagnosing wastes money.
Test one — silicone and grout
Dry the shower fully, then run only the water on the walls (not the floor) for 15 minutes. If moisture appears outside the shower, the wall grout or silicone is failing — a resurface job.
Test two — the hob
Silicone the internal corners, then flood only the shower floor. Fresh water outside the hob within an hour points to the hob joint — the most common failure in 90s bathrooms.
Test three — the membrane
If neither test above triggers, but moisture appears on adjacent walls or ceilings below, the membrane itself has failed. That's a full shower strip.
What each result means for cost
Silicone/grout failure: $300–$900 resurface. Hob joint failure: $900–$2,400 localised repair. Membrane failure: full shower strip and rebuild, $4,500–$8,500 depending on tile choice. Diagnosing correctly saves you from paying rebuild pricing on a resurface problem, or worse — paying resurface pricing on a rebuild problem that returns within six months.
When to call a professional
If you can see visible bubbling paint, dark staining, or mould on the adjacent room's wall or ceiling, stop testing and book an inspection. Water travels laterally along timber joists — the visible damage is rarely under the failure point. Delayed action turns a $2k repair into a $15k floor and ceiling replacement.
Insurance considerations
Sudden bursts are usually covered by home and contents insurance in Victoria; gradual seepage from a failed membrane usually is not. We provide moisture readings and a written diagnosis you can submit with a claim, but we will not misrepresent gradual failure as a sudden event to help an insurance claim succeed.