Question: Is the underfloor space in our 2 lot scheme common property? What can we do if it has been sold to another owner?
I live in a self-managed 2 lot scheme in NSW. One lot sits above the other, and I live on the bottom. The lot above me was recently sold, and it appears that the underfloor space below me has been marketed and sold to the new owners as a cellar.
I do not have access to the underfloor space, but the other owners do. Is the underfloor space considered common property? What can I do about this situation?
Answer: Underfloor space is likely common property if it falls outside the lot boundaries on the strata plan. Access alone doesn’t determine ownership.
In NSW strata schemes, common property is effectively the default position. Anything outside the cubic airspace boundaries of a private lot, as shown on the registered strata plan, is generally considered common property unless clearly stated otherwise, regardless of who has physical access to it.
Here, the strata plan appears silent on the underfloor area, which strongly suggests it is common property, particularly if it falls outside the boundaries of the upper lot’s defined airspace. The first and most important step is to review the registered strata plan to confirm this. In many older two-lot schemes, boundaries can be difficult to interpret without professional assistance, particularly for undercroft storage, roof voids, basements, or subfloor spaces.
If the area is common property, it cannot be privately sold, marketed, or exclusively used by one owner without the proper legal process, and problems commonly arise when such a space is advertised during a sale as though it forms part of the lot despite not being on the strata plan or title. Common property belongs to all lot owners collectively, in proportion to their unit entitlements, and cannot simply be appropriated or sold by one owner for private benefit without formal approval and legal documentation.
Practical next steps
- Obtain a copy of the registered strata plan and review the lot boundaries. If unclear, get advice from a strata lawyer or registered surveyor.
- Ask the other owner how the area was represented during the sale, did the contract, marketing material, or agent describe the cellar as part of the lot?
- Check whether an existing by-law grants exclusive use of the space. In many cases, none exists.
- Going forward, the OC can formalise use either by an exclusive use by-law (which may require compensation reflecting market value), or by a full strata subdivision with updated plans, amended titles, and a general meeting resolution if ownership is to transfer permanently.
- Check the development consent and any planning conditions before any use or conversion as a cellar, since council consent or other approvals may still be required even if the OC agrees to grant exclusive use or sell the area.
This post appears in the August 2026 edition of The NSW Strata Magazine.
Leanne Habib
Premium Strata
E: info@premiumstrata.com.au
P: 02 9281 6440
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