Is your shower leaking? The early signs.

A shower does not fail suddenly. It fails over years, in a predictable sequence, and it gives you plenty of warning if you know what you are looking at. Almost every catastrophic bathroom we strip out on this coast had been signalling for half a decade to somebody who thought it was just a bit grubby.

• 1. Black or lifting silicone. The first domino, usually around year four to six. In our damp air silicone moulds before it splits, so people clean it and move on. Once it has let go at the base, water is getting into the junction.
• 2. Eroded or cracked grout at the floor-to-wall junction. Grout is porous and this is the busiest corner in the room. Missing grout here is water reaching the substrate.
• 3. A musty smell that never quite clears. Not the room smelling damp after a shower. A background smell that is there at 3pm on a dry day. That is something wet inside the structure.
• 4. White powdery efflorescence on the grout. Salts leaching out because water is moving through the material and evaporating. It is not dirt and scrubbing will not fix it. It is a symptom of transit.
• 5. Bubbling paint or a cupped skirting on the other side of the wall. The big one, and it is in the next room, not the bathroom, which is why it gets missed. Your hallway is reporting on your shower.
• 6. Rust at the bottom of the shower screen track. Water sitting where it should be draining away.
• 7. A soft or spongy floor at the shower entry. The end of the road. Once the floor moves under your foot, the substrate is gone and you are renovating.

Sign one is two hundred dollars. Sign seven is thirty thousand. Everything in between is a chance to get off cheaply, and the whole point of this page is that you get about five years of chances.

Two free checks, ten minutes.

The tap test. Take a coin or use a knuckle and tap steadily across your tiles, particularly low on the walls and all around the shower base. A well-bonded tile gives a solid, dead note. A tile that has debonded from the substrate sounds hollow, and tradies call it drummy. Drummy tiles low in a shower mean water is very likely getting behind them. Tiling laid to AS 3958.1 over a sound substrate should not sound hollow anywhere, and a patch of drumminess that is growing year on year is a live problem.

Look at the other side. Go into the room that backs onto your shower wall, the hallway, a bedroom, a linen cupboard, and get down at floor level. Bubbling or flaking paint, a skirting board that is cupping or swelling, a musty cupboard, a carpet edge that feels cool. Water leaves the bathroom before it announces itself in the bathroom. This is the single most useful check on this page and it costs nothing but two minutes.

Leak or condensation? In Devonport, usually condensation.

We would rather say this than sell you a renovation you do not need. Roughly half the leaks we get called to on the North-West Coast between May and September are not leaks at all. They are condensation, and they are fixed with ventilation rather than a strip-out.

Location tells you which one you have. Condensation mould appears high and wide on the cold surfaces: the ceiling, along the cornice, in window reveals, on external walls, spread reasonably evenly around the room. It is warm wet air hitting a cold surface and giving up its moisture. Leak damage is the opposite. It is low and localised, concentrated around the shower base, the wet wall and the floor.

So: mould on the ceiling with a rock-solid floor is a ventilation problem. A properly sized exhaust fan, ducted outside rather than into the roof space, on a run-on timer, usually sorts it. That is a few hundred dollars of electrician, not a renovation. Mould low around the base with drummy tiles and a soft spot is a leak. Both at once is common too, because our climate is generous like that.

Why it is worse here.

Nothing in a Devonport bathroom dries. We get just under 1,000 millimetres of rain a year in a cool maritime climate, our 9am humidity through winter regularly runs above 80 per cent, and July maximums sit around 12 to 13 degrees. A wall cavity that gets damp in May is still damp in September. On the mainland, a small leak of the same size often dries between wettings and eventually shows up as a stain. Ours simply carries on working.

Then there is the substrate. Homes across Devonport, East Devonport and Latrobe built from the 1970s through the early 1990s very commonly sit on particleboard flooring, which swells irreversibly the first time it gets properly wet. There is no drying it out and no reversing it. More on that in our bathroom lifespan guide.

Why there is no such thing as patching a membrane.

People ring us asking to seal a leaking shower, and there is a product for everything, so we understand why. But the membrane sits under your tiles and under your screed, and nothing applied to the top of a tile reaches it. If the membrane is compromised, the only genuine repair is to remove what is above it, install a new membrane to AS 3740, have it inspected, and re-tile: a full renovation at $20,000 to $32,000, per our Devonport cost guide. Which is exactly why signs one through four matter. Silicone and grout are the maintenance layer keeping water off the membrane's weak points. Ignore them and you buy a new bathroom fifteen years early.

A worked example.

A 1987 brick veneer in Ambleside, 2026. The owner called about a musty hall cupboard, which she had assumed was a ventilation problem and had been airing out for two years. The cupboard backed onto the shower wall.

The bathroom itself looked fine. Tiles intact, no obvious mould, floor solid to stand on. But the tap test found a growing drummy patch across the bottom two rows of the wet wall, the silicone at the base had gone years ago, and the skirting in the cupboard was cupped. Water had been tracking behind the debonded tiles into the particleboard for six or seven years.

Full strip-out, a section of floor replaced, two bottom plates renewed, new membrane to AS 3740 with the inspection, re-tile and a new hobless walk-in shower: $29,200. Caught at the black-silicone stage it would have been about $200. Caught at the drummy-tile stage, maybe a $1,400 re-grout and re-seal. The musty cupboard was her last warning, and it was two years old by the time we saw it. Have a look at yours this weekend.