How to Split a Block into Two and Build Two New Homes in Brisbane

Splitting one block into two and building a new home on each lot can be an excellent way to unlock the value of a Brisbane property. It may allow you to create an additional home for family, retain one property and sell the other, build two investment properties, or complete a small development for resale.

However, a successful one-into-two subdivision involves much more than drawing a new boundary through the middle of the land. Zoning, frontage, access, services, stormwater, slope, overlays and the design of the homes can all affect whether the project is feasible.

The best results usually come from considering the subdivision and the two homes as one coordinated project from the beginning.

What does splitting a block into two involve?

In planning terms, dividing one existing property into two separate lots is generally called reconfiguring a lot, or ROL. Most residential one-into-two subdivisions in Brisbane require a development application and planning approval from Brisbane City Council.

Once the subdivision conditions have been satisfied, a survey plan is submitted to Council for plan sealing. The sealed plan can then be registered with Titles Queensland, creating two separate legal titles.

The homes also require their own building approvals and may require additional approvals for plumbing, drainage, operational works, demolition, driveways or work near Council infrastructure.

Is your block suitable for subdivision?

The overall size of the property is important, but it is only the starting point. Two blocks with the same land area can have very different development potential.

A preliminary feasibility assessment should consider:

• Zoning and minimum lot requirements: The applicable zone, neighbourhood plan and subdivision code will help determine the expected lot area, dimensions and road frontage.

• Overlays: Flooding, overland flow, bushfire, biodiversity, heritage, landslide risk and other overlays can change the design requirements or affect developable area.

• Existing house position: If the current home is to remain, there must be enough space to create a compliant second lot while maintaining appropriate setbacks, access and private open space.

• Frontage and vehicle access: Each new home needs safe and practical access. A narrow frontage, corner location or rear-lot arrangement can significantly influence the subdivision layout.

• Slope and retaining: Steep sites may require additional earthworks, retaining walls, structural design and stormwater management.

• Sewer, water and stormwater: Each lot must be capable of being appropriately serviced. The location and depth of existing infrastructure can materially affect both feasibility and cost.

• Easements and Council infrastructure: Existing easements, sewer lines, stormwater pipes or other infrastructure may restrict where boundaries and buildings can be located.

• Trees and vegetation: Protected vegetation or significant trees may affect the proposed boundary, driveway and house footprints.

• The shape and orientation of the land: An irregular site can still work, but the two homes may need to be custom-designed to use the available space efficiently.

Brisbane City Council recommends using City Plan online to identify the property’s zoning, overlays, neighbourhood plan and applicable planning requirements. Because those controls interact, professional town planning advice should be obtained before committing to a design or purchase.

Subdivision or dual occupancy: what is the difference?

These terms are often confused.

A subdivision creates two separate parcels of land with separate titles. Subject to the approval conditions and legal arrangements, the properties can generally be owned and sold independently.

A dual occupancy is a planning use involving two dwellings on one site. It does not automatically create two freehold lots. Separate titling may require a different approval and title structure.

If your objective is to sell the homes separately, give one to a family member, or hold them under different ownership, the intended title outcome should be confirmed at the start of the project.

The typical process for a one-into-two subdivision

1. Complete a development feasibility assessment

Before spending heavily on drawings, engage the right consultants to establish what can realistically be achieved. This may involve a town planner, cadastral surveyor, building designer, builder and civil engineer.

The assessment should consider both planning compliance and construction practicality. A subdivision may appear possible on paper but become unviable if it requires extensive retaining, service upgrades or a home design that does not suit the target market.

2. Prepare the subdivision concept and home designs together

It is risky to finalise the new boundary before confirming that a functional home can be built on each lot.

Early concept plans should test:

• house footprints and setbacks;

• garages, driveways and vehicle movements;

• private open space and landscaping;

• site levels, retaining and drainage;

• service connections;

• privacy, overlooking and neighbouring amenity;

• solar orientation and natural light; and

• the likely expectations of future buyers or tenants.

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Custom-designed homes are often the best solution for newly created or narrow lots because they can respond to the exact frontage, depth, slope and orientation of each property.

3. Lodge the development application

The town planner and project consultants prepare the necessary reports and plans for the subdivision application. Depending on the property and proposal, the application may be code assessable or impact assessable.

Code assessment does not require public notification. Impact assessment generally does and may involve a longer and more complex process.

Council may issue an information request seeking clarification or additional technical material before deciding the application. If approved, the decision notice will include conditions that must be completed before plan sealing.

4. Satisfy the approval conditions and complete civil works

The conditions may require work or documentation relating to:

• water, sewer and stormwater connections;

• driveways and vehicle access;

• earthworks and retaining walls;

• electricity and telecommunications;

• easements;

• landscaping or vegetation;

• infrastructure charges; and

• preparation of the final survey plan.

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Some projects also require an operational works approval before civil work can begin.

5. Obtain plan sealing and register the new titles

Once the relevant conditions have been met and required charges paid, the survey plan is lodged with Council for endorsement, known as plan sealing. The sealed plan is then registered with Titles Queensland to create the two new titles.

The sequencing of subdivision registration and building work should be planned with your surveyor, planner, certifier, lender and builder. The best sequence can depend on finance, existing improvements, service works and the conditions of approval.

6. Obtain building approval and construct the homes

Each home must be designed for its individual lot and obtain the required building approval before construction begins. A private building certifier assesses the plans against the relevant building requirements, while plumbing, drainage and other approvals are addressed as required.

Working with one builder across both homes can help coordinate site establishment, earthworks, retaining, service connections, material selections and construction timing.

How long does it take?

The timeframe depends on the site, category of assessment, quality of the application, Council information requests, civil works and title-registration process.

Brisbane City Council indicates that a code-assessable subdivision application that aligns with City Plan may generally take around three to four months, although it can take longer where further information is required. Eligible applications prepared and certified through the RiskSMART process may be assessed more quickly.

That is only the planning assessment component. Time must also be allowed for design and consultant work, satisfying approval conditions, civil construction, plan sealing, title registration, building approvals and construction of the homes. A realistic project program should be prepared after the property-specific due diligence is complete.

What does it cost to subdivide and build two homes?

There is no reliable flat-rate cost because every site is different. A proper feasibility should make allowances for:

• town planning, surveying, engineering and design fees;

• Council development application and plan-sealing fees;

• infrastructure charges;

• demolition and site clearing, if required;

• sewer, water, stormwater, electrical and telecommunications works;

• driveways, earthworks, retaining and landscaping;

• Titles Queensland registration and legal costs;

• building certification and other approvals;

• construction of both homes;

• finance, interest, insurance and holding costs;

• sales and marketing costs, if the properties will be sold; and

• an appropriate contingency.

The cheapest-looking subdivision layout is not always the most profitable. Spending more on an efficient layout, better street appeal and homes designed for the local market can create a stronger overall result.

You should also obtain independent accounting and legal advice regarding GST, capital gains tax, ownership structure, finance and contracts before proceeding.

Common mistakes to avoid

Assuming the land is suitable based only on its size

Minimum area does not necessarily mean a subdivision will be approved or that two good homes will fit. Frontage, dimensions, overlays, access and infrastructure are equally important.

Buying or designing before checking the services

Moving or extending sewer and stormwater infrastructure can be a major cost. Service investigations should form part of the early feasibility work.

Treating the subdivision and house designs separately

A boundary that satisfies a basic lot-size requirement may leave awkward building envelopes. Test both home designs before finalising the subdivision layout.

Underestimating external and site costs

Retaining, demolition, temporary works, authority connections, infrastructure charges and finance costs can materially affect the development margin.

Designing two generic homes without considering the market

The best bedroom count, parking, living areas, storage and finish level will depend on the suburb and intended buyer or tenant. The homes should be designed around both the site and the market.

Should you retain the existing house or demolish it?

Keeping the existing home can reduce construction scope, but only if it is positioned and serviced in a way that supports the new subdivision. The retained house may need alterations, a relocated driveway, new service connections, updated fencing or improvements to make the completed development feel cohesive.

Demolishing the existing house provides greater freedom to optimise the boundary and design both homes together. However, demolition and holding costs must be included in the feasibility.

The right option should be determined through concept design and cost planning—not guesswork.

Work with a builder from the beginning

Early builder involvement can help ensure the proposed development is not only approvable, but also practical and commercially sensible to construct.

Yellowwood Building Group provides a complete design and construct service for custom homes, knockdown rebuilds, difficult sites and residential development projects across Brisbane and South East Queensland. We can work with the project team to assess the site, develop the two-home concept, coordinate the required consultants and prepare a detailed construction proposal.

If you are considering splitting a block into two and building two new homes, speak with our team before committing to a layout. Early due diligence can identify costly constraints and reveal opportunities to achieve a better design and development outcome.

Contact Yellowwood Building Group

Phone: 07 3540 7822

Email: sales@yellowwood.com.au

This article provides general information only. Planning controls, fees and approval requirements vary by property and can change. Obtain site-specific town planning, surveying, legal, accounting and building advice before making development or financial decisions.

Sources

• Brisbane City Council — Subdividing land

• Brisbane City Council — City Plan online

• Brisbane City Council — Development application types

• Brisbane City Council — Plan sealing requests