In most NSW strata schemes, the owners corporation pays for concrete cancer repairs, because the affected concrete is almost always common property. Under section 106 of the Strata Schemes Management Act 2015, the owners corporation has a strict duty to properly maintain and keep common property in a state of good repair, and to renew or replace fixtures and fittings in it. Structural slabs, carpark structures, external walls and the structural element of a balcony are typically common property under a standard strata plan, which puts them squarely inside that duty.
That answers the first question. It rarely answers the one the committee is actually stuck on, which is how to get the works funded, approved and delivered without the process stalling for two years while the concrete keeps deteriorating. This article covers responsibility by building elements, the approval path, what a defensible scope of works looks like, and the timeline you should plan around.
Your scheme’s registered by-laws can shift some of this, and none of what follows is legal advice. Get your strata manager or a strata lawyer to confirm the position for your building before the committee relies on it.
Who pays, by building element
| Building element | Usually classified as | Who is normally responsible |
|---|---|---|
| Carpark slab, soffit and columns | Common property | Owners corporation |
| Structural balcony slab | Common property | Owners corporation |
| Balcony tiles, floor coverings and finishes added by a lot owner | Lot property or owner-added work | Lot owner, subject to by-laws |
| Waterproofing membrane beneath a balcony slab | Common property | Owners corporation |
| External walls, facade and render | Common property | Owners corporation |
| Structural columns and beams inside a lot | Common property | Owners corporation |
| Internal non-structural walls within a lot | Lot property | Lot owner |
| Balustrades and handrails | Depends on the strata plan and by-laws | Confirm against the registered plan |
The recurring dispute is the balcony. The structural slab and the membrane beneath it are usually common property, while tiling or decking a lot owner has installed over the top usually is not. When concrete cancer is in the slab and the tiles have to come up to reach it, the practical answer is that the owners corporation does the structural work and the by-laws determine who reinstates the finishes. Sort that out in writing before work starts, not after the tiles are in a skip.
Can the owners corporation defer the work?
Only in narrow circumstances. Section 106 allows an owners corporation to determine by special resolution that it is inappropriate to maintain, renew or replace a particular item, but only where doing so will not affect the safety of the building or detract from its appearance. Deteriorating concrete in an occupied carpark fails that test, because falling concrete overhead is a safety issue rather than an aesthetic one.
There is also a consequence for inaction. Section 106 gives an owner a right to recover reasonably foreseeable loss caused by the owners corporation’s failure to comply with its duty. The limitation period for those claims was extended from two years to six years under the Strata Schemes Legislation Amendment Act 2025, so confirm the current commencement position with your strata lawyer. The practical point for a committee is that deferring known structural repairs carries legal exposure, not just deterioration risk.
Who decides, and how the approval actually works
This is where most schemes lose time. The sequence that works looks like this.
1. Get the condition established properly.
A building inspection or engineering report that confirms concrete cancer is the starting document, but it usually will not tell you the true extent. Hammer testing across the affected areas finds delamination that has not yet cracked through the surface, and that is what determines the size of the job. Our post on concrete cancer in Sydney carparks and balconies explains why the visible damage is normally the smaller number.
2. Get a scope of work, not a price.
A scope of works sets out the affected areas, the repair method for each, the products and standards specified (AS 3600 for concrete structures), the access equipment and staging, how variations will be measured, and the warranty. Without one, the committee cannot compare quotes and the general meeting cannot make a defensible decision.
3. Decide the funding route.
There are three practical options: draw on the capital works fund, raise a special levy, or borrow. Section 80 of the Act requires the owners corporation to maintain a 10 year capital works fund plan, and structural concrete conditions belong in that plan. Where the fund cannot cover the works, a special levy raised by resolution at a general meeting is the usual route.
4. Take it to a general meeting.
The works and the funding go to the owners corporation as a motion. Ordinary business of this kind is typically decided by a majority resolution at a general meeting, though the required resolution type depends on what is being approved, so have your strata manager confirm the motion wording. Committees that bring a completed scope of works, comparable quotes and a clear funding proposal to the meeting get decisions in one meeting. Committees that bring a report and a rough figure usually do not.
5. Appoint and stage the works.
Access approvals, resident notification, traffic management for carparks and staging around occupied lots all sit between approval and the first day on site. Build that into the timeline.
What to expect on site
Concrete cancer remediation in an occupied strata building is a staged job, not a single visit. Expect the affected concrete to be broken out back to sound material, the corroded reinforcing steel to be cleaned and treated or supplemented where its section has been reduced, and the surface reinstated with a bonding agent and a polymer-modified repair mortar. Where a failed waterproofing membrane caused the corrosion, the membrane is reinstated as part of the same works, because repairing the concrete alone means repeating the job in a few years.
For carpark repairs, plan for partial closures, resident parking arrangements and traffic management. For balconies, plan for access scheduling with individual lot owners and for noise during breakout. Neither is avoidable, but both are manageable when they are in the program rather than a surprise.
Timelines vary with scope. Contained remediation across a handful of areas commonly runs a few weeks. Multi-level carpark soffits or multi-building schemes can run several months, and staging around occupied lots often affects the program more than the repair work does. Our concrete repairs guide covers the repair types and timeframes in more detail.
Frequently asked questions on Concrete Cancer Repairs for Strata Buildings
Who pays for concrete cancer repairs in a NSW strata building?
Usually the owners corporation, because the affected concrete is normally common property and section 106 of the Strata Schemes Management Act 2015 imposes a strict duty to maintain and repair it. Check your registered by-laws and get advice for your scheme.
Can the owners corporation refuse to do the work because of cost?
Not straightforwardly. Section 106 allows deferral only by special resolution where maintaining the item is inappropriate and doing nothing will not affect safety or appearance. Structural deterioration in an occupied building is unlikely to meet that test, and owners can claim for loss caused by a failure to comply.
Do we need a special levy, or can we use the capital works fund?
Either, depending on what the fund holds. The capital works fund exists for exactly this kind of work, and the 10 year plan required under section 80 should anticipate it. Where the fund is short, a special levy raised at a general meeting is the standard route.
Does the whole owners corporation have to vote, or can the committee just approve it?
Works and funding of this scale normally go to a general meeting rather than being decided by the committee alone. The resolution type depends on the motion, so have your strata manager confirm the wording before the notice goes out.
Who reinstates balcony tiles after the structural repair?
The structural slab and membrane are usually the owners corporation’s responsibility, while owner-installed finishes over the top usually are not. Agree this in writing with affected lot owners before work starts.
How do we know a quote covers the real extent of the damage?
Ask what assessment method was used. If the contractor has only looked at the visible damage without hammer testing the surrounding area, the quoted area is likely to be understated and the price will move once breakout begins.
Stakat Building works with strata committees and owners corporation managers across Sydney on concrete cancer remediation, carpark and balcony repairs, and structural remediation. If your committee needs a scope of work and a written quote it can take to a general meeting, get in touch or call 0427 595 170 for a free site assessment.