If you live in a strata scheme in New South Wales, one of the most important things to understand is what you own as a lot owner, and what belongs to the owners corporation. This is not just a technical issue. It determines who must pay for repairs, who must organise them, who can approve renovations, and what happens when something goes wrong such as leaks, cracked tiles, window damage or balcony defects.

The basic rule is straightforward: common property is the responsibility of the owners corporation, and lot property is the responsibility of the lot owner. The difficulty is that the line between the two is not always obvious. The strata plan is the starting point, but it does not show every detail. When boundaries are unclear, the answer can also depend on the strata legislation, relevant case law and any by-laws made by the scheme.

What is Common Property?

Common property is generally everything in the strata scheme that is not part of an individual lot. The NSW Strata Schemes Development Act defines common property as any part of the parcel not comprised in a lot, including common infrastructure that is not part of a lot.

In practical terms, common property usually includes the building’s structure and the parts that support or protect the scheme as a whole. That often means the external walls, roof, slabs, structural floors and ceilings, windows and balcony doors, and key services such as shared plumbing, electrical wiring, fire safety systems and waterproofing membranes. Even if some of these items are located inside your apartment, they may still be common property if they form part of the building’s structure or shared systems.

The owners corporation has the legal duty to maintain and repair common property, and it uses levies paid by owners to do this work.

What is Lot Property?

Lot property is the part of the building you own privately. Generally, it includes the internal space of your apartment or townhouse and the fixtures and finishes within it, unless the strata plan or by-laws say otherwise.

For most strata schemes registered after 1 July 1974, a practical guide used across NSW is that structures shown on the strata plan with a solid thick line are common property, while structures shown on a thin line are usually lot property. Internal walls that are not shown on the strata plan are usually lot property.

The Key Exceptions You Must Know

Not every scheme follows the same boundary rules. A major exception is that the general post-1974 position does not apply to strata plans registered before July 1974, where boundaries may be defined differently, sometimes using a “centre line” approach.

Also, notations on the strata plan can change the usual assumptions, and approved renovations or special by-laws can shift responsibility for particular items over time. NSW even provides a “common property memorandum” that schemes can adopt to help clarify responsibility, especially where disputes frequently arise.

Because of these variations, there is no single answer that fits every building. When in doubt, it is wise to seek expert advice based on your strata plan and your scheme’s history.

Why This Matters to You as a Lot Owner

This matters because it affects money, repairs, approvals and risk.

If something is common property, the owners corporation must arrange and pay for repairs. If something is lot property, the lot owner pays. Getting this wrong can mean unexpected bills or delays while responsibility is argued.

It also matters for renovations. Lot owners generally cannot change common property without proper owners corporation approval, and in many cases, a by-law is required where renovations affect waterproofing, structure, external appearance or shared services.

Finally, it matters for insurance and liability. Building insurance usually relates to the building and common property, while lot owners insure their contents and improvements. When boundaries are unclear, claims and repairs can be delayed.

A Simple Takeaway

In NSW strata, you usually own the internal finishes and fixtures within your lot. The owners corporation usually owns the structural parts of the building and the shared systems, even if they run through your unit. The strata plan is the starting point, but legislation, case law, notations and by-laws can change the result. If you are unsure, it is better to check early – because the financial and practical consequences of getting it wrong can be significant.

If you need assistance determining whether an item is lot property or common property, please feel free to contact us for a professional, obligation-free consultation.

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