Strata defects are one of the most contested areas of Australian building law, and for good reason. When you buy an apartment, you own your lot — but you share the building envelope, structure, mechanical systems, and common areas with every other owner. That shared ownership creates shared responsibility, and when defects affect shared elements, things get complicated fast.
Whether you’re a lot owner dealing with water ingress in your apartment, a member of the owners corporation (OC) trying to pursue the developer, or someone who’s just moved in and noticed the building isn’t quite right, this guide explains how strata defects work, who is responsible for what, and how to get things fixed.
Lot property vs common property — the fundamental distinction
The most important concept in strata defects is understanding what is lot property (belonging to you as the individual owner) and what is common property (owned collectively by all owners through the owners corporation).
Common property typically includes
- The building structure: foundations, load-bearing walls, roofing, and the building frame
- External walls and the building façade
- Shared corridors, lobbies, and staircases
- Lifts and plant rooms
- Shared mechanical systems: fire systems, ventilation, electrical risers
- Common area finishes: floors, ceilings, and walls in corridors and common spaces
- External windows and doors (in most states)
- Balcony structures (the slab and waterproofing layer beneath tiles)
Lot property typically includes
- Interior walls within your apartment
- Internal finishes: flooring, paint, cabinetry
- Individual plumbing fixtures (taps, toilets, basins)
- Balcony tiles (above the waterproofing membrane)
- Window fittings and locks within the lot
The distinction matters because the OC is responsible for maintaining and rectifying defects in common property, while individual lot owners are responsible for their own lot.
Why this creates complexity
The problem with strata defects is that the source of a defect and its effect are often in different ownership categories. Water ingress in your kitchen ceiling might originate from a waterproofing failure on the common property balcony above you. The damage shows up in your lot, but the cause is in common property — and therefore the OC is responsible for the rectification.
This means that as an individual lot owner, you often can’t pursue the builder directly for defects that originate in common property. The OC must pursue the builder on behalf of all owners. If the OC is slow, passive, or doesn’t have the resources to pursue the claim, individual owners can find themselves stuck.
Types of defects common in apartment buildings
Waterproofing failures
The most common and most costly strata defect category. Waterproofing failures typically occur at:
- Balcony and terrace membranes
- Wet area membranes (shower recesses, laundries) in common property areas
- Rooftop areas and roof gardens
- Below-ground carpark structures
Waterproofing failures allow water to penetrate the building envelope and cause damage that spreads over time — to finishes, structure, and eventually to electrical or mechanical systems.
Façade and cladding defects
Failures in the building’s external cladding system can allow water ingress, compromise fire safety (in the case of combustible cladding), or cause significant visual deterioration. Cladding defects in high-rise buildings have been a major focus of regulatory attention in Australia since the Lacrosse Tower fire in Melbourne in 2014 and subsequent cladding audits.
Fire safety system deficiencies
Fire doors, sprinkler systems, and smoke detection deficiencies are safety-critical. These are treated with urgency in dispute processes and can require emergency rectification. They are always common property matters.
Structural defects
Cracking in the building’s transfer structure, movement in the podium slab, or problems in the foundations can affect multiple lots simultaneously. These are typically the most expensive defects to rectify and carry the longest warranty periods.
Lift and mechanical plant
Lifts, mechanical ventilation, air conditioning plant in roof spaces, and pump systems are common property. Defects in these systems are an OC matter.
Common area finishes
Cracking tiles in corridors, delaminating paint on external walls, or damaged windows in the lobby — these are common property defect matters even though they might seem minor compared to structural issues.
The OC’s role: pursuing the builder for common property defects
When a defect exists in common property, the owners corporation is the party with standing to pursue the builder or developer. Individual lot owners can’t sue the builder directly for common property defects in most states — they need the OC to act.
This is one of the most frustrating aspects of apartment ownership. The OC may not have the funds to pursue a claim, may be passive or controlled by owners who don’t want the disruption, or may be dominated by the original developer through proxy votes if the building is still selling lots.
How to push the OC to act
If you believe there are common property defects that the OC is not pursuing:
- Raise it formally at an OC meeting — put it in writing as an agenda item and request that the committee take advice on the builder’s defect liability
- Request an independent building inspection of common property — this establishes a formal defect report that the OC can act on
- Pass a motion — if you have sufficient support from other lot owners, you can pass a motion at an AGM or extraordinary meeting directing the OC to engage a solicitor and pursue a defect claim
- Apply to the tribunal — if the OC is actively failing in its duty to manage and maintain common property, lot owners can apply to NCAT (NSW) or VCAT (VIC) for orders directing the OC to act
State-specific frameworks
New South Wales
NSW has the most developed strata defect framework in Australia. Under the Strata Schemes Management Act 2015, developers must provide a defect inspection report within 18 months of occupation. The OC has 2 years from the date of occupation to take action on major defects.
The Home Building Act 1989 provides a 6-year warranty for major defects and 2 years for minor defects. Critically, the OC can pursue the builder for common property defects under this warranty — they don’t need individual owner agreement to do so.
NSW Fair Trading and NCAT are the primary dispute resolution bodies. NCAT has jurisdiction to order rectification of defects and can award compensation.
Key timings:
- Developer must provide the initial defect report: within 18 months of first occupation
- OC must take action on major defects (or lose rights): within 2 years of occupation
- Statutory warranty (major defects): 6 years from completion
Victoria
In Victoria, the Owners Corporations Act 2006 governs OC obligations, and the Domestic Building Contracts Act 1995 provides the warranty framework.
The DBDRV (Domestic Building Dispute Resolution Victoria) is the mandatory first step before proceeding to VCAT. The OC can lodge a dispute with DBDRV on behalf of all owners for common property defects. The statutory warranty for structural defects is 10 years.
A significant challenge in Victoria is that the OC must initiate the DBDRV process within the warranty period and must have the backing of sufficient lot owners (typically a majority vote at an OC meeting) to proceed.
Queensland
Under the Queensland QBCC framework, the OC body corporate can lodge a complaint about common property defects. The QBCC has a 6-year and 6-month structural defect warranty period. The body corporate is the complainant for common property matters.
The Body Corporate and Community Management Act 1997 governs how the body corporate must handle maintenance and defect rectification.
Getting an independent building inspection for strata defects
The most effective step an OC can take before engaging in any dispute process is commissioning an independent building inspection report covering all common property. This report:
- Documents every identified defect with photographs and professional descriptions
- Distinguishes between lot property and common property defects
- Provides a rectification cost estimate
- Uses the correct technical language required by tribunals and courts
A building inspection for strata purposes typically costs $2,000–$10,000 depending on the size of the building, and is often funded from OC funds or levied to all owners.
This report becomes the foundation of any claim. Without it, you’re arguing from a position of anecdote. With it, you have a professional, timestamped record of defects attributable to the builder’s work.
Deadlines — why acting quickly matters
Strata defect claims have strict limitation periods, and missing them can be fatal to your case. In NSW, the 2-year window from first occupation to initiate a major defect claim is one of the tightest in Australia. In Queensland, the 6-year and 6-month window sounds long but moves fast when you factor in the time needed to get OC agreement, commission an inspection, and prepare a complaint.
Mark the occupation date of your building and count back from there. If you’re in a building where defects are becoming apparent, act now — don’t wait until the building is visibly deteriorating.
Key takeaways
- Strata defects split between lot property (your responsibility) and common property (the owners corporation’s responsibility) — the origin of a defect, not just where damage appears, determines who acts.
- The OC must pursue the builder for common property defects; individual lot owners generally cannot do so directly.
- Waterproofing failures, façade defects, fire system issues, and structural movement are the most common and costly strata defects.
- NSW has the most developed framework with strict timelines: the OC has 2 years from occupation to take action on major defects.
- Victoria’s 10-year structural defect warranty is the longest in Australia, but the DBDRV process must be initiated first.
- Commission an independent building inspection for common property before entering any dispute — this is the foundation of your claim.
- Act early: limitation periods in strata are real and missing them means losing your rights regardless of how serious the defects are.
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