Common Property in Strata: How to Tell What’s Yours (and What’s Everyone’s) Without Losing the Plot
Look, strata can be a head-spin
Buying into a strata scheme feels easy enough. Nice apartment, decent neighbours, maybe a pool. Thing is… the second something cracks, leaks, or goes clunk in the night, the million‑dollar question pops up: who pays? You? Or the owners corporation? That’s where “common property” vs “your lot” matters. A lot.
Now, here’s where it gets interesting. Common property isn’t just hallways and lifts. It’s slabs, membranes, pipes, wiring, windows, even the voids between walls. And it can shift a little over time with by‑laws and exclusive‑use rights. So, let’s demystify it — practically, in plain English.
The 30‑second version (because no one needs a lecture)
In NSW, your lot is generally the cubic space inside the boundary walls, floor, and ceiling shown on the strata plan. Everything else? Usually common property.
Structural bits (slabs, external walls, waterproofing membranes) are commonly common property.
Cosmetic finishes (paint and carpet inside your lot) are usually yours.
Windows/balcony doors are often common property if they’re in boundary walls.
Pipes and wires are common property until they solely serve one lot and sit within the lot after the last connection.
By‑laws can shift maintenance to owners (think balcony tiles), and exclusive use can look like ownership… but isn’t.
Actually, let’s clarify that. “Exclusive use” doesn’t transfer ownership. It gives the right to use (and usually the duty to maintain). Subtle difference. Big consequences.
What exactly is “common property” — without the gobbledygook
Contrary to popular belief, there’s no single “always/never” list. But a few patterns hold up, especially in NSW:
Boundary structures
External walls, the concrete slab above and below, the roof, columns, beams — commonly common property. Your interior paint? Yours. The concrete it sits on? Not yours.
Windows and balcony doors
If they’re in the boundary wall, they’re typically common property (frames, glass, sashes). Repairs to the mechanism, rot, water ingress? Often the owners corporation. A cracked flyscreen? Usually you.
Balconies and courtyards
Slab and balustrade = common property. Waterproofing membrane = common property. Tiles? Depends. Many schemes shift tile maintenance to owners via a by‑law. Read the by‑laws before committing to a reno or a fight.
Floors and ceilings
Carpet and underlay = lot owner. Timber/laminate floating floor? Usually owner. The slab and acoustic underlay required by by‑law? That gets nuanced fast. Ceiling paint is yours; ceiling void and structure are common.
Services (pipes, wiring, ducts)
Rule of thumb: from the source to the point it only serves your lot = common. After the last junction, if the pipe/wire is wholly within your lot and only services your lot = likely yours. Riser stacks, main ducts, main meters? Common.
Doors, locks, and lobbies
Front door leaf and frame in the boundary wall? Often common property (with owners responsible for the lockset/handle). Internal bedroom doors? Yours. Common lobby, lifts, mailboxes attached to common walls? Generally common.
The voids and the hidden stuff
Cavities, risers, crawlspaces, and ventilation shafts sitting outside your cubic space = common property. If you can’t legally occupy it, assume it’s not yours.
Worth noting: that’s the usual NSW position. Buildings differ by age, plan, and by‑laws. Always start with the strata plan.
How to figure it out in five steps (that actually work)
Get the strata plan and read the legend
It shows lot boundaries: thick lines, notations, reference marks. If the boundary sits at the median of the wall, the middle is the line. If it’s the inner face, everything beyond that line is common. The legend explains it. Dry but decisive.
Check the by‑laws (especially special ones)
A common property rights by‑law may grant exclusive use (and shift maintenance) of courtyards, terraces, storage cages, even windows. There’s also a Common Property Memorandum (in NSW) many schemes adopt, clarifying who fixes what. Gold for maintenance spats.
Identify the asset type
Is it structure (slab, beam)? Finish (paint, tile)? Service (pipe, wire)? Structure and membranes are typically common; finishes inside lots are often not.
Trace services to their “last point”
If the pipe or cable still services multiple lots, it’s common. After it splits and sits within your lot, it’s probably yours. Junctions and valves matter. A plumber’s photo goes a long way.
Remember: exclusive use ≠ ownership
Your courtyard might be common property with exclusive use. That often means you mow it, clean it, maybe repair the pavers. But title doesn’t magically move to your name.
Pro tip: if in doubt, take photos, mark them up, and match them to the plan. Visual beats vague every time.
The waterproofing rabbit hole (because this one’s everywhere lately)
Leaks are the number one strata drama. Here’s the deal:
Waterproofing membranes under bathrooms and on balconies are commonly common property.
Failure of the membrane = often the owners corporation’s gig (section 106 maintenance duty rings a bell).
Tiles on top? Frequently pushed to owners by‑law. Cracked grout without membrane failure? Might be on you.
Water can travel. The wet patch on your ceiling may come from two floors up, not your balcony. Jumping at the first suspect causes expensive detours.
This always surprises people: the origin point decides responsibility, not just where the drip lands.
Real‑world snapshots
A business owner replaces bathroom tiles in a DIY weekend project. A year later, leaks. The new tiles didn’t cause it; the old membrane failed. Owners corporation responsibility. The DIY didn’t help, but it wasn’t the cause.
Someone installs timber floorboards without the acoustic underlay required by by‑law. Noise complaints start. The fix? Painful. New underlay or rugs everywhere. Reading the by‑laws first would have saved cash and conflict.
A family with “their” courtyard discovers it’s common property with exclusive use. Crumbling retaining wall? Owners corporation. Loose pavers? By‑law says the lot user must maintain. Mixed responsibilities, both true.
Common misconceptions that spark avoidable fights
“If it’s inside my walls, it’s mine.” Not if it’s structure or services still serving others.
“Exclusive use means I own it.” Nope. Use rights and maintenance duties can be granted, not title.
“Windows are always my problem.” Usually not, if they sit in boundary walls. Mechanisms and frames are commonly common.
“Any balcony issue is on the owners corp.” Tiles vs membrane matters. By‑laws can shift maintenance for tiles.
“All schemes are the same.” Age, plan style, registered notations, and adopted memoranda change the answer.
Actually, let’s correct one more. Paint inside your lot is yours to fix. But peeling from a leak caused by a failed common membrane? The owners corporation can still be on the hook for the cause and, often, resulting damage.
A simple flow for disputes (keeps tempers cool)
Step 1: Gather evidence
Photos, videos, dates of leaks, expert notes. No shouting matches in the lobby.
Step 2: Plan + by‑laws
Identify boundaries; check any special by‑law shifting responsibility.
Step 3: Notify in writing
Clear, calm note to the strata manager/committee with evidence. Ask for a timeframe to investigate.
Step 4: Expert report if needed
Plumber’s leak detection, builder’s report. Shared access for investigation is part of strata life.
Step 5: Mediation/tribunal as last resort
If nothing moves, formal steps exist. But plenty of matters resolve once the plan and by‑law are put on the table.
Worth noting: insurance sits on top of all this. Building policy often covers common property and sometimes resultant damage; your contents/landlords policy deals with internal finishes and belongings. Two policies, one incident, overlapping coverage. Coordinate, don’t duplicate.
So what does this mean for you?
Before renovating, check the plan and by‑laws. Balcony tiles and windows are trapdoors for the unwary.
For leaks, get the source pinned down. Cause decides responsibility.
For courtyards and car spaces, confirm if it’s on title or exclusive use. The maintenance duty may not sit where you think.
For services, follow the pipe/cable to its last junction. Single‑lot and inside the lot? Probably yours. Before the split? Probably common.
And for peace of mind, document everything. Recent photos and plan extracts win arguments faster than opinions do.
This bit’s understandably confusing. But once the plan/boundary picture clicks, the rest follows pretty neatly.
FAQs people actually ask (over coffee, not a boardroom)
Are windows common property?
If in boundary walls, usually yes (frames, sashes, mechanisms). Flyscreens and internal locks are often the owner’s job.
Who fixes balcony leaks?
The waterproofing membrane is commonly common property. Tiles might be the owner’s if a by‑law says so. Source and by‑law decide.
Is my courtyard mine?
Often common property with exclusive use. You may maintain surface items; structure/retaining walls typically sit with the owners corporation.
What about pipes?
Shared services = common. After the last branch and wholly within your lot = often yours. Junctions and access points are key.
Can by‑laws make me fix common property?
A common property rights by‑law can grant exclusive use and shift maintenance. It needs proper approval and registration.
Do I need approval to replace flooring?
Usually yes for hard floors (acoustics!). Many by‑laws require specific underlays and committee approval.
Who pays for paint damage from a leak?
Building insurance and owners corporation might cover cause and some resultant damage. Internal repaints can be yours absent insurance. Each policy/incident differs.
A calm, neutral next step
If a boundary line or responsibility call is about to turn into a bunfight, a quick plan/by‑law review can save time and tempers. For clear answers on repairs, waterproofing, windows, and exclusive‑use quirks in your scheme, speak with a Strata Lawyer.
Standard legal disclaimer
General information only, not legal advice. Strata laws, plans, and by‑laws vary by scheme and jurisdiction, and change over time. Outcomes depend on your specific strata plan, by‑laws, and facts. Get tailored advice from a qualified practitioner before acting.