Short answer
Common property is everything in a strata scheme that isn’t part of an individual lot — typically the shared structure and areas: external walls, roof, foyers, stairs, driveways, gardens and shared services. It’s owned jointly by all the owners through the owners corporation.
Where the line sits
The exact boundary between your lot and common property is set by the registered strata plan. As a rule, the structural and shared parts of the building are common property, and the inside of your unit is your lot — but the plan is always the final word.
Why it matters
Because common property is shared, maintaining it is generally the owners corporation’s responsibility, not any single owner’s — the roof, external walls, common hallways and shared services. That’s why repair questions so often turn on “is this lot or common property?” (see who’s responsible for strata repairs).
Keeping on top of it
Maintaining common property means tracking obligations, defects and works across the whole building. A self-managed scheme can run all of that with a system such as Straita — logging issues and keeping the records — so nothing on the shared property slips.
Primary sources
- Strata Schemes Management Act 2015 (NSW) — the owners corporation’s duty to maintain and repair common property.
- NSW Government — Strata schemes (Fair Trading) — common property and repairs.