Homes · Strata suites · Rental units
Stain under the shower? Four suspects. One test sequence.
Pan membrane, drain connection, supply lines in the wet wall, or splash past the enclosure — each demands a completely different repair, and demolishing tile to find out is the most expensive diagnostic in residential plumbing. Controlled flood isolation and moisture mapping convict the right suspect first, so the only thing opened is what actually failed.
Free phone consult · No pressure · Mon–Sat 8am–6pm PT
Why showers leak
- Drain-to-membrane connections and blocked weep holes
- Pan membrane fatigue, corner folds, and puncture damage
- Curb and threshold details built without proper wrapping
- Supply and valve connections weeping inside the wet wall
- Grout and perimeter sealant read as 'waterproofing' (they aren't)
- Enclosure gaps letting spray attack the room's weakest seam
The isolation sequence
- 1
Pattern interview
Every use or only some? Long showers or any contact? One user or all? The stain's timing rules suspects in and out before instruments arrive — it's the cheapest test there is.
- 2
Moisture baseline
Thermal and moisture mapping below and around the assembly establish where water has actually been travelling — the footprint that the flood tests must explain.
- 3
Layered flood testing
Drain plugged, pan filled and held; then drain tested alone; then supply pressure-checked; then controlled spray on enclosure seams. Each layer separately, interior monitored — the layer that moves the instruments is the one that's guilty.
- 4
Verdict & scope
A written finding naming the failed layer with test evidence — sized for a plumber, a tile setter, or a sealant tune-up, and formatted for strata and insurance files where they apply.
Owners ask
How do you test a shower pan without tearing out tile?
Isolation flood testing: the drain is temporarily plugged, the pan is filled to a controlled level below the curb, and the assembly is monitored — moisture instruments below, time, and water level tell the story. A dropping level or advancing moisture signature convicts the pan or its drain connection; a stable test acquits them and moves suspicion to supply lines, the valve wall, or splash escaping the enclosure. Every layer gets its own test before any demolition is scoped.
What usually leaks — the pan, the drain, or something else?
Honest spread from BC bathrooms: the drain connection and its weep path lead the league (the joint between membrane and drain body is the assembly's hardest detail), aging pan membranes and corner folds second, supply and valve connections inside the wet wall third — and a meaningful share turn out to be enclosure splash and failed perimeter sealing, which costs hundreds to fix, not thousands. The test sequence exists because each answer sends a different trade.
The stain below appears only sometimes. What does that mean?
Intermittency is diagnostic gold. Stains tracking every use point at the drainage path or pan; stains only with long showers suggest a slow path that needs volume; stains tracking one user usually mean spray patterns reaching a weak enclosure point. We'll ask exactly these questions on the free call — the pattern often halves the suspect list before testing begins.
This is a strata — the owner below is demanding answers. Can you document it?
That's half our strata practice: source determination stated plainly — pan, drain, supply, or splash — with test evidence attached, in a report written for councils, managers, and insurers. It settles the in-suite-vs-building question (and the who-pays conversation that follows) on findings rather than opinions. See our strata services for the full framework.
Bathroom & kitchen leaks·Hidden water leaks·Ceiling moisture detection·Strata services
Test first. Demolish never (or at least, precisely).
Free phone consult — describe the stain's habits and we'll tell you the likely suspect on the call.