Duplex Construction Sydney & NSW

State Property Development builds duplexes and dual occupancy developments across Greater Sydney. NSW Builders Licence 355555C. $20M public liability. HIA Member 1269991. Duplex construction is a core part of our residential work, with completed projects visible on our Projects page including builds at Constitution Hill, Wollongong, and North Ryde.

A duplex is two separate dwellings on one lot, typically built to be Torrens title subdivided into two independently owned properties once construction is complete. This makes duplex construction attractive for owner-occupiers wanting to live in one dwelling and sell or rent the other, and for developers building for sale.

What’s Involved in Duplex Construction

• Design and construct, or construction from your approved drawings
• Dual occupancy DA or CDC approval management
• Shared or separate services design – power, water, sewer connections for each dwelling
• Fire separation between dwellings to NCC requirements
• Torrens title subdivision coordination once construction is substantially complete
• Site works – driveways, landscaping, and fencing for both dwellings

Duplex Construction Costs – Sydney 2026

• Per dwelling: $2,900-$4,200/sqm depending on specification
• Standard duplex (two 3-bedroom dwellings, ~180sqm each): $1.05M-$1.5M total construction for both dwellings
• Larger or premium specification duplexes: priced individually based on size and inclusions

These figures are construction only and exclude land, demolition of any existing structure, subdivision costs, and site-specific works such as retaining walls or extended service connections. We assess your specific site and provide a detailed costing before you commit to a design.

Approval Pathway

Dual occupancy development in NSW requires either a Development Application (DA) or, where the site meets specific criteria under the NSW Low Rise Housing Diversity Code, a Complying Development Certificate (CDC). The CDC pathway is faster but has strict eligibility requirements around lot size, width, and zoning. We assess your site against CDC criteria before recommending a pathway.

Torrens title subdivision – splitting the duplex into two separately titled and separately saleable properties – requires a separate subdivision application, typically lodged once construction is substantially complete. We coordinate with your surveyor on subdivision timing so it doesn’t delay your ability to sell or settle either dwelling.

Real Duplex Projects

We’ve completed duplex construction across Sydney, including builds at Constitution Hill and Wollongong. Photos of completed and in-progress duplex work are on our Projects page – real builds, not stock photography.

Disclaimer: All prices shown on this website are indicative estimates only and are provided as a general guide. Final construction costs will vary depending on architectural design, structural engineering requirements, hydraulic design, BASIX/NatHERS compliance, geotechnical (soil) reports, site conditions, council or certifier requirements, selected finishes, inclusions, and overall project scope. A detailed quotation can only be provided once all relevant plans, reports, and specifications have been completed and reviewed.

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