Leaking Shower

Failed waterproofing, the 90s-2000s defect

The leaking shower

The membrane under the shower tiles has failed and water is going into the wall and floor instead of the drain. It is the most common hidden repair in houses built from 1985 to 2010.

What is actually happening

Modern showers rely on a waterproof membrane under the tiles, not the tiles themselves. Membranes installed before AS 3740 tightened in the 2000s, or installed badly since, fail at the corners, the hob and the drain. Water tracks into the frame, rots the bottom plate, lifts the tiles next door and shows up as a stain on the ceiling below or a soft skirting in the hallway. Grout and silicone are cosmetic; they are not the waterproofing.

The signs

  • Stains or bubbling paint on the ceiling or wall directly below or beside the shower
  • Soft, swollen or lifting skirting outside the bathroom
  • Tiles that sound hollow or drum when tapped
  • Grout that cracks and regrows mould within months
  • A musty smell in the bathroom that cleaning does not shift
The proper fix

Strip the shower base and lower wall tiles, remove the failed membrane, treat or replace rotten framing, apply a new membrane to AS 3740 with a certificate, retile. Regrout-and-seal products are a stopgap, not a fix, and they void the argument about who caused the damage if it worsens.

What it costs, South Australia
Leaking shower fix (strip, waterproof, retile base)$2,500 – $6,500
Shower regrout and reseal$600 – $1,600
Full bathroom renovation (mid-range)$18,000 – $42,000

Indicative 2026 ranges, not quotes. All costs

When to walk away

No, but price it in. Walk away if the leak has been running for years and the floor joists or bottom plates are rotten across more than the bathroom, or if the same "fix" has been applied more than once.

Where it turns up

Suburbs in our street DNA set whose era mix and soil make the leaking shower a regular. Not a survey; a pattern.

Questions

Is a leaking shower covered by home insurance?+

Usually not. Insurers treat failed waterproofing as gradual deterioration or a maintenance issue. Sudden burst pipes are covered; slow leaks are not.

Is a leaking shower the landlord's problem?+

Yes. It is a property defect, and in both SA and Victoria a shower you cannot use is an essential-service failure and an urgent repair.

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