A deck is usually the cheapest way to add real living space to a house, so it's no surprise it's one of the first jobs people ask us to price. The catch is that "how much for a deck" is a bit like asking how much for a car. It depends what you're building, what it's sitting on, and how hard it is to get to.
We build decks across Wollongong, the Illawarra and the Southern Highlands, everything from a low platform off the back door to a raised entertaining deck stepping down a sloping block. Here's how the money actually breaks down, so you can read a quote and know what you're looking at.
Rough ranges for 2026
Decks are usually priced per square metre, and in NSW in 2026 a built deck generally runs somewhere in the low-to-mid hundreds of dollars per square metre, supplied and installed. Where you land inside that comes down mostly to the timber and the height.
- A low treated-pine deck on flat ground, close to the ground, sits at the affordable end.
- A merbau or spotted-gum deck at a normal floor height, with a hardwood you'll oil rather than paint, sits in the middle.
- A raised deck with a tall subframe, stairs and a balustrade, especially on a slope, is the dearest because most of the work is underneath where you can't see it.
As a rough feel, a small deck off the back of a house is often a few thousand dollars, a decent entertaining deck runs into five figures, and a big raised deck on a steep block can go well past that. Treat those as a starting point, not a quote. Every block changes the number.
How much does it cost to build a deck per square metre?
Built decks in NSW are generally priced in the low-to-mid hundreds of dollars per square metre, supplied and installed. Two things decide where inside that a job sits: the decking timber you pick, and how far off the ground the finished floor lands.
Height is the one people underestimate. A per-square-metre rate assumes a certain amount of framing under the boards, and a deck at floor level needs a full subframe, deeper footings, posts, stairs and a compliant balustrade before a single board goes down. That structure doesn't add any deck area, so it lifts the rate rather than the size.
The same square metre also prices differently in treated pine, merbau and composite. Our merbau vs composite decking comparison puts the material choice side by side.
How much does a covered deck cost?
A covered deck costs meaningfully more than an open deck of the same size, because you're building two structures instead of one: the deck below and a roof, posts and beams above it. The roof also has to tie into the existing house and stay watertight where it meets, which is skilled work rather than framing time.
Budget for it as two line items and you'll read quotes far more easily. The deck is priced on area and height as above. The cover is priced on span, whether it's an open pergola, a solid roof or an insulated panel, and how the flashing into the house is handled.
Approval is the other difference. An open deck and a pergola can each qualify as exempt development on their own, but combining them, or putting a solid roof on, can push the job onto a different path. We build both, and our pergolas and carports page covers the cover side.
What actually moves the price
Roughly in the order it bites:
- The timber. Treated pine is the cheapest and takes paint or stain. Merbau and spotted gum cost more but hold up better outdoors and look the part. Composite (more on that below) costs more again up front.
- Height off the ground. A deck 300mm off the lawn is quick. Once you're up at floor level or higher, you're into a proper subframe, footings, stairs and a compliant balustrade, and that framing is where the hours go.
- The slope and the ground. A flat, easy block is cheap to set out. A slope, rock, or reactive clay means deeper footings and more posts.
- Access. If we can get materials and a bobcat to the spot, great. Carrying everything through the house or down a side path by hand adds time to every trip.
- The extras. Stairs, a balustrade, screening, lighting and a roof over the top are all separate line items. A bare platform and a covered entertaining deck are very different jobs.
Timber or composite?
This is the question we get most. Timber is cheaper to build and looks fantastic, but it wants a re-oil every year or two to stay that way. Composite (a wood-and-plastic board) costs more up front and doesn't have the same grain, but you wash it instead of oiling it, and it won't splinter or grey off.
Neither is "better." If you love the look of real hardwood and don't mind a weekend of oiling now and then, go timber. If you'd rather never think about it again, the extra spend on composite buys you that. We build both and we're happy to tell you honestly which suits how you actually live.
Do you need council approval?
Often, yes. A low deck under a certain height and floor area can be exempt development in NSW, but once a deck is raised, attached to the house, or over roughly a metre off the ground, it usually needs approval, either as a Complying Development Certificate or through council. It's worth knowing before you start, because it changes the timeline. We sort that path as part of the job so you're not chasing it yourself.
Getting a real number
The only way to know what your deck costs is to have someone stand on the spot, look at the height and the ground, and price the actual build. If you're weighing one up anywhere around the Illawarra, we're happy to come out, talk through timber versus composite, and give you a fixed-price proposal you can compare against.
Want a hand with this at your place? Get a free quote or call 0434 037 851.