Waterproofing failures cause most building leaks
Behind the tiles in every shower and under the surface of every balcony is a waterproofing membrane. When it's installed well, you never think about it. When it fails, through age, movement, poor detailing or damage, water gets into framing, walls, slabs and the rooms below, often for months before anyone notices.
We investigate leaks properly before quoting, because re-grouting a shower with a failed membrane underneath, or coating over a balcony that doesn't drain, just delays the next leak. Once the source is confirmed, we strip back, replace the waterproofing to the relevant Australian Standard, reinstate finishes, and repair the damage the leak caused.
What we waterproof
Showers & bathrooms
Leaking showers, bath hobs, wet-area floors and laundries, waterproofed to AS 3740.
Balconies
Tiled and membrane balconies leaking into rooms or units below, to AS 4654.
Roof decks & podiums
Trafficable membranes over occupied spaces and car parks.
Planter boxes
Strip, re-membrane, drain and reinstate leaking planters.
Retaining walls
Back-of-wall waterproofing and drainage where accessible.
Basements
Damp and leaking basement walls and floors investigated and treated.
Signs of failed waterproofing
- Swollen or stained skirting and door frames next to bathrooms
- Loose, drummy or cracked tiles in showers and balconies
- Mould and musty smells that keep coming back
- Water stains on ceilings below bathrooms or balconies
- Efflorescence (white salt deposits) on balcony edges and soffits
- Ponding water on balconies that doesn't drain
- Damp patches on walls behind showers
Why waterproofing fails
| Cause | Where we see it |
|---|---|
| Membrane missing or too thin | Older bathrooms, cheap renovations |
| Failed junctions and upturns | Shower hobs, door thresholds, wall junctions |
| Poor falls to drains | Balconies and wet-area floors that pond |
| Blocked or undersized outlets | Balconies, roof decks, planter boxes |
| Building movement cracking the membrane | Slabs, timber-framed bathrooms |
| Root and soil damage | Planter boxes |
| Age and UV exposure | Exposed membranes on roofs and decks |
Water coming through a ceiling?
If water is near light fittings or electrics, switch off that circuit if it's safe. We can investigate the source and make safe, including the electrical side.
Our waterproofing process
- InvestigateInspect both sides of the leak, check falls, drains, junctions and moisture readings.
- Report and quoteExplain the source and the repair needed, with options where they exist.
- Strip outRemove tiles, screeds and failed membrane back to a sound substrate.
- PrepareRepair substrate, correct falls, install bond breakers and puddle flanges.
- MembraneApply membrane to the relevant standard, then flood test where appropriate.
- Reinstate and make goodTiles, finishes and any leak-damaged ceilings, walls and framing repaired.
Strata waterproofing
In apartment buildings, waterproofing failures in balconies, roof decks, planter boxes and podiums are among the most common and costly defects, and a leak in one lot often damages another. We investigate and repair common property waterproofing for strata managers, and work out the source so responsibility is clear. See strata maintenance.