Subdivision rules in the ACT

F01 sets general requirements before any zone-specific number. Requirement 6 says subdivision or consolidation is only permitted where each subdivided block has utilities infrastructure. Requirement 8 says subdivision or consolidation is only permitted in residential zones where a new dwelling can be accommodated on the block in accordance with the Territory Plan, or where a dwelling already lawfully exists and any building on the consequent lease is or can be designed to comply.

That second test is the ACT's answer to the minimum lot size question. Rather than a single number, a proposed block has to be shown capable of holding a compliant dwelling: site coverage, storeys, setbacks, building envelope, solar envelope and private open space all have to fit. The zone policy and the technical specifications supply those figures, and the height and setback guide walks through them.

Heritage registered blocks carry an extra test under requirement 7, and consolidation in RZ1 has its own rules in requirements 9 and 10, which limit consolidating previously consolidated blocks and require a consolidated block to yield more dwellings than the blocks it replaces.

RZ1 gets specific numbers. Requirement 11 permits subdivision under the Planning Act to create one or more additional blocks where each subdivided block contains a lawfully constructed dwelling, or each subdivided block is a minimum of 350m². The two limbs are alternatives, so a block that is split around two existing lawful houses is not held to the 350m² floor, while a vacant split is.

Requirement 12 governs unit titling of multi-unit housing in RZ1. It is permitted where all dwellings have been lawfully constructed and either the block is a standard block of at least 600m², or it is a non-standard block. Note 1 adds that staged development under the Unit Titles Act is not permitted for less than five units, which rules out staging a dual occupancy.

A standard block, per the Dictionary, is one originally leased or used for one or two dwellings, or created by consolidating such blocks. Most suburban RZ1 blocks are standard, so the 600m² figure is the one that usually applies to a dual occupancy. Zones RZ2 to RZ5 have no equivalent numeric floor in F01. The general tests and the zone's density and site coverage rules do the work there.

Unit title subdivision is the ACT's equivalent of strata. Section 17 of the Unit Titles Act 2001 applies to a parcel whose lease has at least 50 years to run, and lets the lessee apply to the Territory Planning Authority for approval of the subdivision of the parcel. The application divides the parcel into class A or class B units, any unit subsidiaries and common property.

Section 20 sets the approval test. The authority may approve the application only if it is in accordance with the Act, each unit is suitable for separate occupation, and the proposed use for each unit is permitted under the lease and consistent with any development approval under Chapter 7 of the Planning Act, including its conditions. The unit plan follows the DA, never the other way round.

For a dual occupancy this produces a fixed order of events. Obtain development approval for the two dwellings, build them so they are lawfully constructed, satisfy F01 requirement 12, then lodge the unit title application. Selling one dwelling before that sequence is complete is not possible.

F01 requirement 5 is absolute. Subdivision is not permitted to provide separate title, including subdivision under the Unit Titles Act 2001, to a secondary residence in all zones, to an individual boarding room in all zones, or to community housing in RZ1 and the Community Facilities Zone. A granny flat stays with the main house for as long as it exists.

This is why the choice between a secondary residence and a dual occupancy has to be made at the design stage. A secondary residence is capped at 90m² and cannot be titled. A dual occupancy is assessed as multi-unit housing, faces the density and site coverage limits, and can be unit titled on a qualifying block. The two pathways cannot be swapped after approval without a fresh application.

Subdivision is also assessable development under the Planning Act, so section 143 applies: it needs development approval, and the exempt development regulation offers no route around that for the creation of new residential blocks or units.