In a strata building? Work involving waterproofing generally needs owners corporation approval before it starts. How approval fits in
Why waterproofing matters more in an apartment
Everywhere, waterproofing decides whether a bathroom lasts. In a strata building, it also decides whether your renovation becomes someone else's problem.
A failed membrane in a unit sends water through the slab penetrations and cracks into the ceiling of the apartment below. The first sign is often not in your bathroom at all — it is a brown stain or bubbling paint in your neighbour's bathroom ceiling.
That is why an owners corporation cares so much about the waterproofing specification, and why we do too.
Signs a shower is leaking
In your own apartment: - Grout on the shower floor that is dark, cracked or missing. - Tiles that sound hollow or have lifted. - Swollen skirting or door jambs at the bathroom door. - A musty smell that does not clear.
In the unit below: - Staining, bubbling or flaking paint on the bathroom ceiling. - A damp patch that grows when the shower above is used.
Common property and responsibility
In many NSW strata plans, the boundary of your lot is the inner surface of the walls, floor and ceiling. On that basis, the concrete slab — and often the membrane on it — is common property, while the tiles and fittings are yours.
Some owners corporations have passed by-laws transferring responsibility for bathroom waterproofing to individual owners. Some have not. The strata manager can tell you where the line sits in your building, and it matters for both who pays for repairs and what approval you need.
New buildings and defect warranties
Waterproofing defects are among the most common problems in recently built apartments.
Under the NSW Home Building Act, residential building work carries statutory warranties: six years for major defects and two years for other defects. Waterproofing failure that causes water to enter the building can fall into the major-defect category.
If your building is young and the bathroom is leaking, speak to the strata manager before calling a renovator. The owners corporation may already be pursuing the builder for defects across multiple units. Renovating privately can complicate that claim and leave you paying for work the builder should have fixed.
What proper waterproofing involves
Strip to the slab. The old membrane and screed come out. The slab is inspected for cracks and the penetrations for damage.
Preparation. The slab is cleaned, primed and repaired where needed. Bond breakers go into internal corners and at the floor-wall junction so the membrane can move.
Puddle flanges and penetrations. Each waste receives a flange bonded into the membrane, so water on the membrane drains away rather than tracking along the outside of the pipe.
Membrane. Applied in the specified coats and thickness, over the whole floor and up the walls to the required heights, with the shower recess fully enclosed.
Cure and flood test. Each coat cures before the next. Before tiling, the shower area is flood tested where appropriate.
Screed and tile. The screed forms the falls, and the tiles go on above.
Certificate. A compliance certificate for you and for the owners corporation.
The laundry counts too
A burst washing-machine hose is one of the most common causes of water through an apartment ceiling. Laundry floors are waterproofed on our jobs, and a water-stop valve or burst-proof hoses are a cheap addition.
Where it sits in the program
Waterproofing follows strip-out and rough-in and comes before tiling. The process page shows the full sequence.
Call 02 4601 3371 or send the room details through.
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Questions people ask before they commit
Water is coming through my ceiling from the unit above. What should I do?
Tell the strata manager or building manager in writing straight away, with photographs. They coordinate investigation, because the source may be the unit above's bathroom, a common-property pipe or the membrane — which in many strata plans is common property. Do not wait for the neighbour to fix it privately.
Who is responsible for a leaking bathroom membrane in a strata building?
It depends on your strata plan and by-laws. In many NSW strata plans, the boundary of a lot is the inner surface of the walls, floor and ceiling, which makes the slab and often the membrane common property. Some owners corporations pass by-laws making owners responsible for bathroom waterproofing. The strata manager can tell you what applies in your building.
My apartment is only a few years old and the shower leaks. Should I renovate?
Talk to your strata manager first. Under the NSW Home Building Act, statutory warranties cover defective residential building work — six years for major defects, which can include waterproofing failure, and two years for other defects. A leaking bathroom in a young building may be a defect claim against the builder, and renovating it privately can complicate that.
What certificate do I receive?
A waterproofing compliance certificate from the licensed applicator, identifying the membrane system and confirming it was installed to the Australian Standard. In a strata building, give a copy to the owners corporation as well as keeping one yourself.