The most common job on this site
Thin cover, full weather exposure, and a membrane that failed years ago. Balconies are where this problem shows up first and costs most.
If a Brisbane walk-up has concrete cancer, the balconies almost always have it first. Concrete Cancer Brisbane arranges inspection and repair across the 1960s to 80s unit stock where this is close to universal.
Three reasons compound. A balcony is a cantilever, so it carries its load through the top layer of reinforcement — which is also the layer closest to the weather. The slab is thin, so cover to that steel is minimal to begin with. And it relies on a waterproof membrane which, on a building of this age, has almost certainly failed or was never there.
Water gets through cracked tiling or a failed membrane, reaches the top steel, and the corrosion then shows up on the underside as staining and then spalling. By the time an owner below notices lumps on their balcony, the top reinforcement — the structurally important layer — has been wet for years.
This is where balcony budgets go wrong. Repairing the concrete without renewing the waterproofing simply resets the clock: the same water takes the same route back to the same steel. A proper balcony job is concrete repair, then a new membrane, then screed and finish, then a working drainage fall and a functioning threshold detail at the door.
That reinstatement is frequently half the cost, and it is the half committees forget to budget. A quote covering only the concrete is not wrong — it is incomplete, and worth asking about explicitly.
Balustrade fixings set into deteriorating concrete are a safety matter rather than a maintenance one. Where a handrail moves under hand pressure, that balcony should be taken out of use rather than added to a programme. It is also the point at which the lot-versus- common-property boundary tends to matter most — see the body corporate guide.
On a three storey walk-up you can often scaffold a stack of balconies and work down them efficiently. Doing balconies one at a time as owners complain is the most expensive possible order, because access gets mobilised repeatedly. Where money is tight, staging by stack rather than by individual unit is almost always cheaper overall.
Most of the stock affected is the 1960s–80s walk-up belt and the bayside strip, where salt air reaches the steel faster.
Tell us what the concrete is doing. We will arrange an inspection and a written scope your committee can actually price.
