Building a new house is the one job where people most want a number before they've told us anything about the block. Fair enough, it's a big spend and you want to know if it's even in reach. But the honest answer to what it costs to build a house depends on things we can't see from a phone call: your land, your size, and how you want it finished.
We build new homes across Wollongong, the Illawarra and the Southern Highlands, from straightforward single-storey homes on flat blocks to two-storey builds stepping down the escarpment. Here's how the money actually works, so a quote stops being a mystery.
The build is only part of the spend
When people picture the cost of a new home, they picture the house. The bricks, the roof, the kitchen. That's the biggest number, but it isn't the whole bill, and the bits around it are where budgets quietly blow out.
Roughly, a new build breaks into three buckets:
- The house itself. The structure, the fit-out, the finishes. Priced per square metre, this is the number everyone quotes.
- Site costs. What it takes to make your specific block buildable: earthworks, retaining, drainage, rock removal, a longer driveway.
- The soft costs. Design, engineering, council or certifier fees, home building compensation cover, and connecting power, water and sewer.
Two identical houses can land a long way apart once the site and soft costs are in. That's the part a cheap headline "from" price leaves out.
Rough per-square-metre ranges for 2026
New homes are usually priced per square metre of floor area, and in NSW in 2026 a built home generally runs somewhere in the low-to-mid thousands of dollars per square metre for a standard build, climbing well past that for a high-end one. Where you sit inside that comes down to size, storeys and finish.
- A modest single-storey home on an easy, flat block sits at the affordable end.
- A larger family home with better joinery, stone benchtops and decent bathrooms sits in the middle.
- A two-storey home on a difficult block, with the finishes to match, is the dearest, because you're paying for structure, engineering and site work on top of the house.
As a rough feel, a smaller new home is a serious six-figure spend, and a big two-storey build on a tricky site goes a good deal higher. Treat any per-metre figure you read online as a way to sanity-check a quote, not as your quote. Every block moves it.
Is there an average cost to build a house in NSW?
There's an average published for every state, and it's close to useless for budgeting a real house. A NSW average blends a small project home on a flat estate block with a custom two-storey build on the escarpment, and your job sits somewhere across that spread rather than neatly at the middle of it.
Use an average, or a building cost per square metre, the way you'd use a car's fuel rating. It's a sanity check, not a price. What you're actually paying for is the floor area, the number of storeys, the finish level, and what your particular block needs before a slab can go down. Two houses of the same size on the same street can be tens of thousands apart on site costs alone.
If a new home price comes in well under everyone else's, look at the allowances and the exclusions before you celebrate. That's almost always where the difference is hiding.
What moves the number most
In roughly the order it bites around here:
- The block. Plenty of Illawarra and Southern Highlands land is sloped or sitting on rock. That means deeper footings, more engineering, sometimes retaining walls and piering before the house even starts. A flat, stable block is the cheapest thing you can build on.
- Size and storeys. Square metres cost money, and a second storey adds a staircase, more structure and stronger engineering. Going up is dearer per metre than spreading out.
- Finishes. Tiles, joinery, benchtops, tapware and flooring can swing a budget more than people expect. The same floor plan can cost wildly different amounts depending on what goes in it.
- Coastal conditions. Closer to the water, the wind and salt ratings lift the spec on things like windows, fixings and cladding.
- Access. A tight site where trucks and a crane can't get near adds time and hand-work to nearly every trade.
The costs people forget to budget for
The catch-outs are almost always the same ones:
- Connecting services, especially if power or sewer is a long run from the street.
- The driveway, paths, fencing and landscaping, which never come in the base house price.
- Council or private certifier fees, and the home building compensation cover on residential work over the threshold. The NSW Fair Trading building and renovating pages spell out the contract and insurance side worth reading before you sign anything.
- A contingency. Every site has at least one surprise, and a build with no allowance for it is a build that overruns.
Fixed price, and what "allowances" really mean
A fixed-price contract is only as fixed as its allowances. If a builder pencils in a small tiling or lighting allowance to make the headline number look sharp, you'll pay the difference later when you pick what you actually want. We'd rather price allowances close to what real people choose, so the number you sign is close to the number you pay. Read the inclusions, not just the total.
What's involved in building a house in NSW?
Six stages, in this order: assess or buy the land, design the house to suit it, get approval, sign a fixed-price contract, build, then handover. Approval is either a complying development certificate signed off by a private certifier, or a development application through your council, and which one your block lands on shapes both the timeline and the fees.
Two parts catch people out. The design and approval stage runs for months before anything visible happens on site, which how long it takes to build a house sets out stage by stage. And the builder you sign with moves the final number more than the floor plan does, because the contract, the allowances and the supervision decide whether the price holds. Choosing a home builder in NSW covers what to check before you sign, and CDC vs DA in NSW explains which approval path you're likely on.
If you're comparing a new build against keeping your block and starting over, our guide to knockdown rebuild cost in the Illawarra walks through the demolition side, and if a second dwelling is on your mind, what it costs to build a duplex covers that path. Going up instead of out is its own decision, covered in the cost of adding a second storey.
If you want a sense of where the market sits, the ABS publishes building activity data for Australia, though state averages only tell you so much about your street.
What does it cost to build a house on your own land?
Owning the land already takes the biggest line off the total, but it doesn't change the build price. You still pay the same three buckets: the house per square metre, the site costs your block needs, and the soft costs of design, engineering, approval and service connections. The land only ever affected the first of those indirectly, through what it's like to build on.
What owning the block does change is how much you already know. A block you've lived on for years comes with a known driveway, services at the boundary and a soil type the neighbours can tell you about, which takes some guesswork out of the site costs. If there's a house on it now, add demolition and disconnection to the list, and read our knockdown rebuild cost guide before you assume the old slab is any use.
Larger blocks in the Southern Highlands are the other case. A long run from the street to the house makes power, water and the driveway real numbers, and bushfire mapping can lift the construction standard of the whole house. Both belong in the budget before the plan is drawn, and new build site costs goes through them.
How much does it cost to build a unit?
On an ordinary residential block in NSW, a unit you build yourself is either one half of a duplex or a granny flat, and the two are priced very differently. A single dwelling in a duplex generally lands around $400,000 to $650,000 to build, because it's a full-sized home sharing a wall and a slab. A granny flat is capped at 60 square metres of internal living space, so it's the cheapest self-contained dwelling you can add to a block by a long way.
Which one you can build comes down to the block and the zone. A duplex needs enough land to meet the minimum lot size and frontage for two dwellings, and goes through complying development or a DA depending on the block. A secondary dwelling can usually go through complying development on a block of 450 square metres or more. Our guides to the cost of building a duplex and granny flat costs have the detail for each.
How do you pay for building a house?
You pay in stages, not up front. A NSW home building contract sets out a deposit and then progress payments tied to work actually completed, and the standard stages are the slab, the frame, lock-up, fixing and practical completion. Each claim falls due when that stage is done, so the money follows the house rather than running ahead of it.
The deposit is limited by law. On a contract over $20,000 a builder can't take more than 10 per cent up front, and has to give you a certificate of home building compensation cover before taking it. If you're borrowing, the bank pays each progress claim after its own valuer confirms the stage is complete, which is one reason a clear schedule with well-described stages matters to you and the lender both.
Read the payment schedule before you sign, and match each stage to something you can see on site. Choosing a home builder in NSW covers the contract clauses worth checking, and what to check at handover explains how the final payment and the defects list fit together.
Getting a real number for your block
The only way to know what your house costs is to have someone look at the land, talk through the size and finish you actually want, and price the real build. That's what we do. Have a look at how we handle new homes and knockdown rebuilds, then call us on 0434 037 851 or get in touch through the contact page for a proper, no-pressure quote.
Want a hand with this at your place? Get a free quote or call 0434 037 851.