How much does it cost to build a duplex in Sydney?
The useful answer is a price for both homes and a clear list of what that price covers. Two duplex quotes can look close and describe very different projects, so the list matters as much as the number.
What we're pricing right now
Based on the duplexes we're pricing for clients at the moment, a medium-finish duplex costs about $1.2 million to $1.3 million to build, for both homes. That's for a duplex with:
- Hebel construction
- 3 m ceilings on the ground floor and 2.5 m upstairs
- Floor-to-ceiling tiles in the bathrooms
- 4 to 5 bedrooms and 3 bathrooms in each home
- A single garage for each home
- Our standard medium inclusions list
Higher-end duplexes start at around $1.8 million and go past $2 million. Add a basement or other extras and the price keeps climbing.
Indicative build prices for both homes. Land not included. Not a quote.
The size of each home moves the number most, followed by the finish level, the number of bathrooms and garages, and how complex the design is.
What should sit beside the build price
Put these next to any duplex price and ask whether each one is included, an allowance, or separate:
- Design and approvals: design, engineering, surveys, BASIX and the CDC or DA fees
- Demolition and site preparation: removing the existing house, excavation and any retaining
- Services: water, sewer, electricity and stormwater for two homes, including any Sydney Water requirements
- External works: two driveways and crossovers, fencing, landscaping
- Titles: the cost of separate titles, if you plan to sell or refinance one home
- Council contributions and the long service levy, where they apply
Why two quotes for the same plans differ
It's usually scope. One quote includes the driveways and lists the appliances by model. Another leaves out the external works and carries a low appliance allowance. The totals look close, but the homes aren't. Ask for the written specification and the list of exclusions and allowances before you compare.
Where your block changes the cost
The same pair of homes costs more on a sloping block, on poor ground, where the sewer main runs through the site, or where stormwater has to be piped a long way. A site assessment before design starts catches most of these early.
How we price a duplex
We look at the block first. Our free site assessment checks the zoning, lot size, frontage and approval route, and gives you an indicative price range based on our inclusions. If you already have plans, we price them for free. Detailed costings are a separate paid stage, quoted before we start, and the build itself is on a fixed-price contract.
This article is general information. Prices are indicative, exclude land, and vary with the design, site and specification. They are not a quote.
Related: duplex builders in Sydney, the free Duplex Guide and building a duplex on a corner block.