Definition of stratum lots and easements

General requirements

Stratum lots and easements are defined by planes the height and depth of which must be related to AHD or other datum approved by the Surveyor General.

Suitable bench marks must be shown on the plan as set out in cl.13 and 62 Surveying Regulation 2006.

A horizontal plane can be defined by one (or more) reduced levels.

An inclined plane must be defined by three (3) reduced levels.

  • The levels should relate to corners of stratum lots.
  • The corners selected should be as evenly spaced across the plane as is reasonably possible.
  • Levels should be shown in sections, elevations and any statements defining stratum, eg "lying between horizontal planes at RL s......and.......AHD".

Unacceptable stratum definition

The following must not be used to define stratum lots and easements.

  • geometric shape or part of a geometric shape being whole or part of a sphere, cone or helix
  • reference to the material of a structure, and/or
  • a natural feature.

Reference to a natural or structural feature may be shown as a feature on the plan provided the stratum boundary of the lot or easement is defined by reference to AHD.

Where any structure or fence is shown as a feature in a boundary related to AHD, the feature does not constitute a "monument" and the requirements of cl.64(1)(c) Surveying Regulation 2006 regarding structures within 1 metre of a boundary apply.

Plan presentation

The plan must contain sufficient information to adequately define the stratum of each lot or easement and comply with cls.13 and 62 Surveying Regulation 2006. Reduced levels should relate to each corner of the stratum lots. Where the stratum subdivision is complex it may be necessary to show several plan views at different levels.

In a stratum subdivision, the plan view must be supported by:

  • a statement defining the stratum of lots - see example 2 and/or side elevations, cross sections see example 3 and/or isometric drawings.
  • where the stratum subdivision is complex it may be necessary to show several plan views at different levels. The level at which the view is taken should be clearly defined - see example 5 and example 6.

Areas of stratum lots

Areas are to be shown only in the plan view. When there is more than one part to a lot either,

  • The total area of the lot can be shown together with the number of parts of that lot appearing on the plan eg 300m2 (5 parts), or
  • An area can be shown for each lot or part lot at every stratum level shown in the plan. If a lot is shown in two or more parts on one stratum level a total area should be shown for that level.

Isometric drawings

In order to assist interpretation of a stratum plan LPI encourages the use of isometric drawings in the form - shown in example 4.

Elevations

An elevation is the representation of a lot viewed from a particular side - see example 1. A boxed statement should be provided to support the definition.

Cross-sections

A cross section is the representation of the stratum, on a vertical plane, of the lots visible when viewed along a designated line. The designated line is referred to as the section line. The section line must be identified in both the plan view and the cross-section.

The direction of view is shown in the plan views by arrows at the terminals of the section line see example 4.

Statements used to define the stratum of lots and easements

The definition of every stratum lot must be supported by a boxed notation eg.

LOT 1 IS THE STRATUM LYING BETWEEN HORIZONTAL PLANES AT RL's 16.4 AND 79.1 AUSTRALIAN HEIGHT DATUM.

LOT 2 COMPRISES THE STRATUM ABOVE AND BELOW LOT 1 AND IS EXCLUSIVE OF THAT LOT.