Where the water is escaping decides everything
A shower has three lines of defence: the surface layer of tiles, grout and silicone, the waterproofing membrane beneath, and the drainage connections at the waste. Tile-on repairs work when only the surface layer has failed, because water that gets past cracked grout or perished silicone in small amounts is caught by an intact membrane below. Once the membrane itself has failed, water is reaching the wall frame and subfloor directly, and nothing you apply from above the tiles reaches the problem. That is the entire decision in two sentences, and it is why diagnosis matters more than anyone selling a one-day miracle wants you to think. Anyone who quotes a tile-on seal without working out which layer failed is guessing with your wall cavity.
How we work out which layer has failed
We diagnose before we recommend, using moisture meter readings on the walls behind and beside the shower, inspection of the grout, silicone joints and screen seals, flood testing of the shower base with the waste plugged, and thermal imaging where the wetness pattern is unclear. As of 2026, leak detection runs $200 to $500 or more depending on access and how elusive the leak is. The patterns tell the story: damp appearing only after long showers points at surface entry, damp that persists days after the shower was last used points at a saturated substrate and a failed membrane, and water appearing at the ceiling below during use with dry walls above often points at the waste connection rather than the membrane at all.
What the symptoms usually mean
| What you see | Most likely failure | Tile-on repair realistic? |
|---|---|---|
| Cracked or powdery grout lines, damp after long showers | Surface layer | Yes, in most cases |
| Perished or mouldy silicone at corners and screen | Surface seals | Yes |
| Water escaping at the shower screen frame | Screen seals and fixing points | Yes |
| Ceiling damage below, walls dry | Waste or trap connection | Sometimes, via the waste, no tiles disturbed |
| Damp persisting days after use, swollen skirting nearby | Membrane failure | No, honest answer is strip-out |
| Tiles drummy or lifting, efflorescence at edges | Saturated bed under tiles | No |
What a tile-on repair actually involves when it is the right call
A proper tile-on repair is more than a bead of silicone. Failed grout is raked out and replaced, typically with epoxy grout which is itself waterproof rather than merely water resistant, all movement joints and the screen are stripped of old silicone and resealed, and penetrations around tap flanges and the rose are sealed. Done on the right shower, meaning one with an intact membrane, this stops the leak and buys years of service. Pricing depends on the shower's size and condition, so we quote it on inspection after the diagnosis rather than off a script. What we will not do is apply a clear surface coating over the top of failed waterproofing and call it fixed, because we would be back within the year and you would be worse off.
When strip-out is the honest answer, and what that means in Queensland
If the membrane has failed, the repair is a new membrane, and the membrane lives under the tiles. There is no honest path around that. The rebuild is regulated work: in Queensland, waterproofing of internal wet areas must be carried out or supervised by an appropriately QBCC licensed person, built to AS 3740, and certified. That certificate matters beyond compliance, because insurers and future buyers ask for it, and an uncertified shower rebuild can surface in a pre-purchase inspection years later. A strip-out and rebuild of the shower area is effectively a small bathroom renovation, and our bathroom renovation tiers as published on our pricing page are the right way to budget it. It is more money than a reseal, and it is also the last time you spend money on that shower for a very long time.
The cost of guessing wrong outruns the cost of diagnosis
The expensive path is not strip-out. The expensive path is two years of a slow leak soaking a timber-framed wall while a cheap surface seal hides the evidence, and in our experience the worst structural repair bills come from showers that were resealed twice without anyone testing the membrane. Spend the $200 to $500 or more on proper leak detection first. If the answer is a reseal, you saved thousands. If the answer is strip-out, you found out while it was still a bathroom job instead of a carpentry job.
Shower leaking? Get the diagnosis before anyone sells you a fix. Call Hills Plumbing & Gas on 0472 657 042 or book through our leak detection service page, and we will tell you straight whether your tiles can stay. QBCC licence 15243081.
Sources: AS 3740 waterproofing of domestic wet areas; QBCC waterproofing licensing and certification requirements; Queensland Building and Construction Commission guidance on defective waterproofing. Check current requirements before arranging work.