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The information provided in this guide is not intended to amount to legal advice. Professional assistance may be required to determine the most appropriate action to protect your legal rights. Please read our Terms of Use on the Strata Titles Policy and Procedure Guides web page. Landgate accepts no responsibility where parties print this guide and seek to rely on information that is out of date.

Individual strata lots are usually very small and the unit value of the land (and buildings) is high. So although the nature of the boundary definition is different, the need for accuracy of definition can be among the greatest of any type of subdivision and the consequences of errors or mistakes can be serious.

It is important that the surveyor uses professional ethics and puts in place an individual quality control process to ensure a high standard of survey. Surveyors must follow the regulations of a TLA survey.

1. Types of Lots

There are two types of lots under the STA, each using different lot boundary definitions:

  • Strata lots are cubic space or spaces (i.e. three dimensional) referenced to a building which is shown on a Strata Plan.
  • Survey-strata lots are defined by dimensions and survey information similarly to a TLA subdivision on a Survey-Strata Plan. They may be restricted vertically or unlimited in height and depth.

1.1. Strata Lots

Lots in strata schemes commonly use buildings to define all or some lot boundaries. Strata lots always remain within the confines of the parcel boundaries. Encroachments that extend beyond the parcel boundary can be treated as either common property or part of a lot depending on whether the strata company or the adjoining strata lot owner is responsible for the control and management of the encroachment.

Section 3(2) of the STA specifies the horizontal and vertical boundaries of the cubic space that can form each of the lots. This section also provides for variation of the boundaries of the cubic space to accommodate a specific circumstance. When a variation occurs, the boundaries described must relate to a wall, floor or ceiling. However, clause 3AB of Schedule 2A of the STA accommodates boundary definitions for “single tier strata schemes” by allowing boundaries to extend to the external surfaces of buildings.

Certain schemes will need obvious variations to wordings to fit specific circumstances. It is important that retaining walls, garden brick or stone walls and walls that extend from a building are defined so there is no confusion on ownership. Section 3(2)(b) of the STA allows for the wordings to meet specific needs.

1.1.1. Wording for all Strata Lots

If it is intended to keep the structure of buildings as common property or if it is a high rise building Regulation 15(2)(f) of the Strata Titles General Regulations 2019 (ST(G)R) states that if section 3(2)(a) applies to the floor plan, the scheme plan must contain a statement to the effect that the boundaries of the lots or parts of the lots which are buildings are the inner surfaces of the walls, the upper surfaces of the floor and the under surfaces of the ceiling. Therefore, the following wording could be used:

“Under section 3(2)(a) of the Strata Titles Act 1985, the boundaries of the lots or parts of the lots which are buildings shown on the Strata Plan are the inner surfaces of the walls, the upper surface of the floor and the under surface of the ceiling.(see Plan Example 18).

and for part lots that are external to the building a wording similar to the following could be used:

“the stratum of the part lots external to the buildings extends between 5 metres below and 10 metres above the upper surface level of the lowest ground floor of the building located on each respective lot except where covered”.

Note: The above wording is a guide only and may not be appropriate for Part Lots labelled Courtyard; Carbay; Terrace; Balcony etc. Every cubic space outside the building that forms a Part Lot must be clearly defined with reference to stated surfaces (see Plan Example 1 and Plan Example 6).

Section 3(2)(a) STA may not be appropriate so section 3(2)(b) may need to be used. Regulation 6 ST(G)R states that for the purposes of section 3(2)(b):

  • if the cubic space is within a building that is not a single tier building, the boundaries of the cubic space must be described:
    • in the case of a vertical boundary, if the base of any wall corresponds substantially with any line referred to in paragraph (a) of that definition, by reference to the inner surface of that wall; and
    • in the case of a horizontal boundary, if any floor or ceiling joins a vertical boundary of that cubic space, by reference to the upper surface of that floor and the under surface of that ceiling.
  • if the cubic space is within a building that is a single tier building, the boundaries of the cubic space must be described in a manner that unambiguously defines the cubic space and its location in relation to the relevant building.

Surveyors should use their professional judgment and where appropriate obtain legal advice to select the appropriate wording so there is no confusion as to the boundaries. For instance, if it is intended to clarify the ownership of floor tiles within a multi-tier building to be defined under either section 3(2)(a) or 3(2)(b), the wording in the building boundary statement on the plan could refer to the upper surface of the floor slab, which would suggest that the floor tiles are owned by the lot owner.

For a single tier scheme, if Schedule 2A clause 3AB is to apply, the following wording could be used if the building and attachments (see Schedule 1 clauses 4 and 5 of the ST(G)R are to be included as part of the lot as per regulation 15(2)(g) of the ST(G)R.

“Under clause 3AB of Schedule 2A of the Strata Titles Act 1985, the boundaries of the lots or parts of the lots which are buildings shown on the Strata Plan are the external surfaces of those buildings”.

and if applicable,

“Where 2 lots have a common or party wall or have buildings on them which are joined, the centre plane of that wall, or the plane at which they are joined, is the boundary”.

Schedule 1 clauses 4 and 5 of the ST(G)R outline the things attached to a building which are (clause 4) and are not (clause 5) to be included as part of a building when using Schedule 2A clause 3AB of the STA.

In the case where part lots are created outside the building a wording similar to the example below should be used:

“The stratum of the part lots external to the buildings extends between 5 metres below and 10 metres above the upper surface level of the lowest ground floor of the main building located on each respective lot, except where covered”.

This will ensure the cubic space above and below the buildings remains as “common property” (see Plan Example 16).

Surveyors and developers may however endeavour to include the areas above and below the buildings as part of the strata lot. The following wording or similar may be used on the floor plan of the strata plan:

“The stratum of the part lots, including the cubic space above and below the part lots comprising buildings, is limited between 5 metres below and 10 metres above the upper surface level of the lowest ground floor of the main building appurtenant to their corresponding Lot number, including where covered” (see Plan Example 17).

Surveyors may wish to seek legal advice as to the use of the above wording.

Note: “5 metres below and 10 metres above” is only used as a sample. Surveyors must look at each scheme and select the appropriate dimensions.

There are no regulations for defining height by Australian Height Datum (AHD) but in certain strata schemes a more precise datum for horizontal height definition may be critical. If possible, surveyors should:

  • use heights above AHD to define all of the strata lots (if practical this is the preferred method)

or

  • reference floor levels between buildings within the scheme.

If surveyors wish, they may reference AHD level to the floor of a building so the stratum of the scheme can be linked to AHD. This is advisable where accurate height definition is critical or where a building or part of a building is to be demolished and reconstructed. Surveyors should use their professional judgement on these issues.

For vacant lot strata plans, as a guide, the wording to describe the vacant lot may read:

"The stratum of Lot 2 extends between 5 metres below and 10 metres above the upper surface level of the lowest ground floor of the building erected on Lot 1"

or similar wording that clearly and unambiguously defines the Lot (see Plan Example 2).

1.2. Survey-Strata Lots

Lots created on a Survey-Strata Plan may be unlimited in height and depth (i.e. no AHD is necessary) or may be limited in height and depth using AHD levels. If limited in height and depth, the lot must have common property above and below it (see regulation 12(4),  Plan Example 3, Plan Example 4 and Plan Example 29).

Note: Plan Examples 3 and 4: Where area designated as common property is intended to restrict the height of another Lot, if there is an existing building on the land, then a notation on the plan should show reference to a stated surface of that building.