The short answer
Shower pan and enclosure leaks release water into the floor assembly beneath instead of onto the bathroom floor, so they are usually discovered from the room below. Because the leak is slow and continuous, subfloor and framing damage is often extensive by discovery, and repair normally means rebuilding the shower rather than patching it.
Where the failure is
The waterproofing layer beneath a tiled shower, the pan membrane, the drain connection, or the seal at the curb and corners, is what keeps water in. When it fails, tile and grout above it continue to look perfect.
Enclosure leaks at the door, the curb or a wall junction produce a similar result outside the shower footprint.
Why the damage is advanced by discovery
The leak occurs every time the shower is used, for as long as it is used. That is a repeating, localised wetting cycle over months or years.
Subfloor, joists and the bottom plates of adjacent walls take it, and by the time a ceiling stain appears below, the assembly has usually been wet for a long time.
Start the restoration request
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Send the address, callback number and a short description of the damage. You do not need to diagnose the problem before requesting help.
Repair usually means rebuild
Once a pan membrane has failed, patching from above is rarely durable. The tile, mortar bed, membrane and often the substrate come out and the assembly is rebuilt.
That is a bathroom renovation in practice, and its cost usually exceeds the drying and structural repair around it.
Testing instead of guessing
Distinguishing a pan failure from a supply leak or a splash problem matters, because the repairs are completely different.
- A flood test of the pan with the drain plugged
- Running the shower with the enclosure dry to isolate splash
- Checking the ceiling below during and after use
- Inspecting the curb and door seal separately
- Moisture readings in the framing below
- Checking the supply and valve behind the wall separately
Structural questions below
Long-term wetting of joists can produce decay, which is a structural repair instead of a restoration one. Where framing has softened, a competent contractor or engineer decides what is required.
Do not let that assessment be skipped because the visible problem was a stain on a ceiling.
Doing the rebuild properly
This is a system, not a product. Membrane, drain assembly, slope to drain, curb detailing and wall waterproofing have to work together, and a failure in any one reproduces the problem.
It is worth using someone who builds showers regularly rather than treating it as tiling.
Second-floor bathrooms in older Greater Burlington homes
Bathrooms added to upper floors of older Burlington-area houses during past renovations frequently sit over original framing that was never intended to carry a wet room, and the waterproofing standards of the era they were installed in vary widely.
In converted multi-unit buildings, a shower leak in an upper unit becomes the downstairs neighbour's ceiling, which turns a maintenance question into a shared-responsibility one. Establishing the boundary in the governing documents matters before the repair is scoped.
Shower leaks: where and what
| Area | What may fail | Consequence |
|---|---|---|
| Pan or liner | Membrane or seams | Water into the floor assembly |
| Drain connection | Seal around the drain | Slow continuous leak |
| Enclosure and curb | Grout, corners, threshold | Wet framing and subfloor |
| Room below | Where staining shows | Discovery is often late |
Clear answers
Common questions
Why is the framing damaged if the leak was slow?
Because it repeated every time the shower ran, for months or years. Repeated localised wetting is harder on materials than one larger event.
How can tile look perfect and still leak?
The waterproofing is beneath the tile, not the tile itself. A failed pan or membrane passes water into the structure while the visible surface stays sound.
Authoritative references