Can I build a dual occupancy on my Canberra block?

By Alessandro Tarzia · Builder & Director, Ottimo Homes · 15+ years' industry experience · ACT Builder Licence 20121515

For some homeowners, these changes may make a second dwelling or another form of low rise housing possible where it was not previously permitted. However, the reforms do not mean every residential block can automatically be developed. What is achievable still depends on the zoning, Crown lease, block characteristics, existing trees, services and the proposed design.

What changed under the Missing Middle Housing Reforms?

Before the reforms, an RZ1 block generally needed to be at least 800 square metres to accommodate two dwellings. That minimum block area requirement has now been removed.

The previous blanket limit of two dwellings in RZ1 has also been replaced by dwelling density guidance and site specific design controls. This means some suitable RZ1 blocks may potentially accommodate more than a dual occupancy.

Multi-unit housing is now a permissible use throughout the RZ1 and RZ2 zones. RZ1 remains a low rise zone, with buildings generally limited to two storeys and a maximum height of 8.5 metres. Multi-unit housing in RZ2 can generally reach three storeys and 10.5 metres.

For multi-unit housing in both zones, maximum site coverage is generally 45 per cent of the original block area. The current technical specifications also include benchmarks for planting area, tree canopy, private open space, parking, setbacks, solar access and privacy.

These controls, rather than block size alone, will often determine what can realistically be achieved.

What is a dual occupancy?

Under the ACT Territory Plan, dual occupancy housing refers to land that was originally used or leased for a single dwelling and is then developed with two dwellings.

The homes may be attached or detached. Depending on the block, they may be positioned side by side, one behind the other or designed to address two street frontages on a corner block. It may also be possible to retain an existing home and add a second dwelling where the existing building and site layout allow it.

A dual occupancy is different from a secondary residence, sometimes called a granny flat. A secondary residence remains associated with the main home, is limited to a maximum dwelling size of 90 square metres and cannot be separately titled. A dual occupancy is treated as multi-unit housing and is assessed under different planning requirements.

Does your block qualify?

The removal of the old minimum block size does not mean block size is no longer important.

The ACT Missing Middle Housing Design Guide identifies blocks larger than approximately 600 square metres as typically suited to dual occupancy. This is design guidance rather than a new legal minimum, so a smaller block is not automatically excluded. It does indicate that fitting two well designed homes becomes more challenging as the available land decreases.

Important considerations include the block’s width, shape, slope and orientation, as well as existing buildings, easements, significant trees, driveway access and available space for parking and landscaping.

The Crown lease must also be reviewed. Some leases only authorise one dwelling and may need to be varied before additional homes can be approved. Heritage requirements, district policies, utility infrastructure and other site specific planning controls can also affect the result.

Could your block support more than two dwellings?

Possibly. The new rules go beyond dual occupancy and allow consideration of tri-occupancies, townhouses, terraces and low rise apartments in RZ1 and RZ2.

The appropriate number of dwellings is not determined by block area alone. It depends on whether the proposed development can satisfy the applicable density, site coverage, height, setbacks, parking, open space, tree canopy, solar access and neighbourhood amenity requirements.

For some sites, two generous homes may remain the best outcome. On a larger, wider or well positioned block, another missing middle housing type may make better use of the land. A preliminary feasibility assessment should compare the available options before the project is limited to one particular layout.

Can the dwellings be separately titled?

The new rules provide more flexibility around subdivision and titling, but separate titles are not automatic.

In RZ1, subdivision can create one or more additional blocks where every resulting block either contains a lawfully constructed dwelling or has an area of at least 350 square metres. This does not mean every 700 square metre block can simply be divided into two 350 square metre blocks. Each proposed block must still have a workable shape, access, services and enough room for a compliant dwelling.

Unit titling may also be available after the dwellings have been lawfully constructed. Specific requirements apply, including a 600 square metre minimum for unit titling multi-unit housing on a standard RZ1 block. Different provisions may apply to non-standard blocks.

The preferred ownership structure should be considered early because it can influence the design, services, approvals, finance and eventual sale of the homes.

Lease variation and the current LVC reduction

Where a Crown lease needs to be varied to allow additional dwellings, a Lease Variation Charge may apply.

The ACT Government currently offers eligible RZ1 and RZ2 missing middle developments a 50 per cent reduction in their codified Lease Variation Charge. The time limited scheme includes conditions such as entering the LVC Deferred Payment Scheme, receiving development approval before 30 June 2029 and completing all dwellings by 31 December 2030.

Eligibility should be confirmed before relying on the reduction when preparing a project budget.

Approval pathways

A dual occupancy or other missing middle development will generally require development approval before building approval can be obtained.

The development application must respond to the Territory Plan, the relevant district and residential zone policies, the Residential Zones Technical Specifications and the Missing Middle Housing Design Guide. A Crown lease variation, government referrals or public notification may also form part of the process, depending on the proposal and site.

Starting with a design that responds to the current planning controls usually results in a clearer and more efficient approval process.

Practical considerations

Beyond planning approval, the project needs a practical servicing and construction strategy.

Water, sewer, stormwater, electricity, metering, waste collection and vehicle access must be considered alongside parking, private open space and landscaping. Demolition, retaining walls, site levels, tree protection and utility upgrades can also have a significant effect on the cost and viability of the development.

If separate titles are proposed, the access, servicing and boundary arrangements should be designed around the intended ownership structure from the beginning.

Getting started

The first step is a preliminary feasibility assessment of the block rather than immediately preparing full architectural plans.

This should confirm the zoning, Crown lease, deposited plan, easements, trees, site constraints, likely planning envelope, potential dwelling yield and preferred title structure. A builder, designer and planning consultant can then develop a concept that responds to the site and provides a realistic basis for costing.

To see how these projects come together in practice, have a look at our completed dual occupancy in Canberra or our townhouse construction in Canberra. For detail on how Ottimo Homes approaches this type of project from feasibility to handover, visit the dual occupancy builder in Canberra page.

Official ACT resources

The following ACT Government pages set out the current rules. Block specific planning, legal and financial advice may still be required.

• ACT Planning: Missing Middle Housing Reforms
• ACT Planning: Territory Plan technical specifications
• ACT Planning: major plan amendments

This information is general in nature and current at July 2026. Planning controls, Crown leases and site conditions vary, so site specific planning, legal and financial advice should be obtained before making commitments.