Rust stains on the balcony slab edge, cracked concrete, or pieces falling onto the balcony below. Concrete cancer on balconies is one of the most common defects in Sydney apartment buildings from the 1960s to the 1990s, and one of the most argued about at strata meetings.
What it is
Concrete cancer is spalling caused by corroding steel reinforcement. Water and salt reach the steel, it rusts and expands, and the concrete cracks and breaks away. On balconies, failed waterproofing and thin concrete cover are the usual causes. See what is concrete spalling for the detail.
Who pays?
In most NSW strata schemes the balcony slab is part of the building structure and therefore common property, so concrete cancer repairs to the slab are usually the owners corporation's responsibility, funded from the capital works fund or a special levy. Tiles, balustrades and waterproofing can differ depending on the strata plan, by-laws and any past renovations, so always check your scheme's documents and get advice if it is unclear.
How repairs are usually organised
- Inspection and report. An engineer or remedial builder inspects all balconies, not just the obvious one, and identifies the extent of damage.
- Specification. An engineer specifies the repair method so every quote prices the same work.
- Quotes and approval. The committee compares itemised quotes and the owners corporation approves the work and funding.
- Repairs. Damaged concrete removed, steel treated or replaced, slab edge rebuilt, balcony re-waterproofed and re-tiled.
- Documentation handed to the committee for the building records.
Why fixing one balcony is rarely enough
Balconies in the same building were built the same way, at the same time, with the same exposure. If one has concrete cancer, others usually have it starting. A building-wide inspection lets the owners corporation plan repairs in one program, which is usually cheaper than calling a builder back balcony by balcony.
Safety first
If concrete is falling, restrict access below and get a make-safe inspection straight away. Loose concrete over walkways, driveways or neighbouring balconies is a genuine risk.
DBP registered for Class 2
Balcony remedial work on apartment buildings is generally regulated building work under the Design and Building Practitioners Act 2020. METCON is registered General Unrestricted (BUP4254812). See our concrete cancer repair service or call 0415 840 500 for an inspection.
Frequently asked questions
Is concrete cancer on a balcony the owners corporation's responsibility?
Usually, because the balcony slab is part of the building structure and therefore common property. Check your strata plan and by-laws for finishes, waterproofing and past renovations.
Should the whole building be inspected?
Yes. Balconies built at the same time usually deteriorate the same way, and a building-wide program is usually more cost-effective than repairing one at a time.
Is concrete falling from a balcony an emergency?
It can be. Restrict access below and arrange a make-safe inspection straight away.
