Artist's impressionDuplexes
Duplex builders across Sydney
Live in one and sell the other, keep both, or house two generations on one block. Whichever it is, we look at the block before we talk about designs, because the block decides most of it.
Start with the block
A neighbour's approval tells you the street is worth a look. It does not tell you what your block can take.
Lot size, frontage, slope, easements, where the sewer runs, flooding, heritage and trees all change what is possible and what it costs. Our free site assessment looks at your address and comes back within two business days with what we can see, what still needs checking and the likely approval route. It is an initial review. It is not an approval and it is not a guarantee.
Since February 2025 the State's Low and Mid-Rise Housing Policy has changed the numbers on eligible land within an 800 metre walk of nominated stations and town centres. It is not automatic approval, it does not cover whole suburbs, and exclusions apply. We tell you which route fits your site and what that means for your timeline before any drawings are paid for.
What a duplex really costs
The build price is only part of it
Demolition, sewer and stormwater works including on-site detention, retaining walls, rock, tree removal, service connections, certification and subdivision can add a significant amount to the number on the builder's quote. We price those site costs separately so you see the whole project, not just a square metre rate.
Two quotes on the same plans can be a long way apart because they include different things. Ours list the inclusions, the exclusions and the assumptions so you can compare them properly.
Step by step
How we run a duplex
Test the site
Planning, frontage, access, services and the likely approval path. Free, within two business days.
Set the brief and budget
Client priorities, floor area and target budget shape the design.
Design and price together
Architecture, engineering, services, subdivision and trade pricing move together.
Build from a settled scope
One program and one site team for both residences, a weekly update while we build, and a defects walk with you before handover.
Duplex work
Selected duplex projects across Sydney
Campbelltown Upper
Two complete homes on one Campbelltown site, each with its own entry, privacy and street presence.
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Appin
Two duplex projects carried through as one coordinated build, with each home resolved as an independent place to live.
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Artist's impressionSouth Wentworthville
A knock down rebuild duplex where the water main sits on the far side of the road, so the Sydney Water connection was planned and approved before the slab.
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Artist's impressionCanley Vale
A knock down rebuild duplex on an established Canley Vale street, currently in delivery.
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Artist's impressionCaringbah
A duplex at Caringbah, in the Sutherland Shire, currently in delivery.
See the project →Duplex rules by council
The rules change at the council boundary
Minimum lot size, frontage, whether you can get two titles and whether complying development is an option all depend on which council your block sits in, and on whether it is on eligible land in a mapped Low and Mid-Rise Housing area. These pages set out the duplex rules for the councils where most of our duplex enquiries come from. They are a first check, not a property entitlement.
Sutherland Shire
600 square metres in R2, with no single local DA frontage minimum.
Ryde
580 square metres and 15 metres of primary road frontage for an attached duplex.
Parramatta
600 square metres and 15 metres of frontage to a public road.
Cumberland
550 square metres; DCP frontage 15 metres attached, 18 metres detached side-by-side.
Blacktown
500 square metres attached, 600 square metres detached.
The Hills District
600 square metres attached, 700 square metres detached.
Canada Bay
Attached: 450 square metres and 14 metres wide. Detached: 800 square metres and 17 metres, or 14 metres on a qualifying corner or parallel-road lot.
Common questions about duplexes
Can I build a duplex on my block?
It depends on the zoning, lot size, frontage, slope and constraints such as easements, flooding or heritage. Send us the address and we will tell you what we can see within two business days. It is an initial review, not an approval.
Do I automatically get two titles?
No. Building approval does not give you separate titles. Subdivision is its own step with its own conditions, and we flag it at the start so the end result you want is planned for.
Will my project be CDC or DA?
Many Sydney duplexes can go through complying development (CDC) when they meet all the standards, which is usually faster. Others need a development application through council. We tell you which route fits your site before any drawings are paid for.
How long does a duplex take?
Most of the time is spent before the build, in approvals and site preparation. We give you a realistic program for your site at the estimate stage rather than a generic number.
Can you build from my existing plans?
Yes. Send the latest drawings for a free estimate on NeoGen inclusions. If you want to progress, detailed costings are quoted as a paid stage before we start them.
What does a duplex cost in Sydney?
It depends on the block, the specification and the site works. Rather than quote a square metre rate that leaves out half the project, we give you indicative pricing on NeoGen inclusions from the site assessment, then detailed costings, quoted as a paid stage, once the scope is clear.
Tell us the address and what you want the duplex to achieve.
Send the address and what you want to build. Within two business days you will have a written site assessment and a clear next step.