How Much Does a Deck Cost to Build in Australia?
Per square metre prices for 2026, what pushes a deck from cheap to expensive, and the approval question to settle before you order a single board.
Prices checked 21 October 2026. Ranges are for Sydney metro, mid-range finishes, supply and install, including GST.
Deck costs per square metre
Decks are usually quoted per square metre because the variables are height, access and material, not room count.
| Job | Typical range | What you get |
|---|---|---|
| Treated pine deck | $350 to $650 per m2 | The cheapest credible option, needs oiling or staining every one to two years |
| Hardwood deck | $550 to $950 per m2 | Merbau, spotted gum or blackbutt. More stable, more expensive, lasts decades if maintained |
| Composite deck | $600 to $1,100 per m2 | No oiling, consistent colour, gets hot underfoot in full sun |
| Deck with roof or pergola | Add $400 to $900 per m2 | Roof structure, roofing material, and usually a council approval |
| Balustrade | $250 to $600 per linear metre | Required above a certain height, and the rules are strict |
A realistic 25 square metre treated pine deck, ground level, easy access, comes in around $9,000 to $16,000 supplied and built. The same deck in hardwood is $14,000 to $24,000.
What changes the price
- Height off the ground. Anything above about a metre needs deeper footings, bracing and balustrade. That is where decks get expensive fast.
- Access. A backyard you can reverse a ute into is cheap. A deck three metres up a side path with no vehicle access is not.
- Footings and soil. Sand, clay, rock and slope all change the footing design and the digging time.
- Size and spacing. Bearer and joist sizes are set by span tables. Bigger spans mean more steel or bigger timber.
- Approvals. Some low decks are exempt development, many are not. Height, size, proximity to boundaries and whether the property is bushfire or flood affected all matter. Check with your council before you buy timber.
- Drainage. Water that used to run through the yard now lands on a deck. It has to go somewhere.
Timber, hardwood or composite
Treated pine is the value pick. It is soft, it moves, and it needs re oiling every year or two, but the installed price is the lowest and it will last 15 to 25 years if maintained.
Hardwood is the tradie's pick. It is harder, more stable, takes a finish better, and looks better as it ages. It costs roughly 50% more than pine.
Composite is the low maintenance pick. No oiling, no splinters, no annual weekend lost. It costs more than hardwood up front, and it is noticeably hotter underfoot in direct sun.
Whatever you choose, the frame underneath is the part that decides whether the deck is still flat in ten years. Do not let anyone save money on the frame.
Deck building checklist
- Confirm whether you need approval, in writing, before ordering materials.
- Ask for the footing design and the timber sizes, not just a total price.
- Check the builder holds a licence for the value of the job. Decks are building work, not handyman work.
- Confirm the balustrade meets the current requirement if the deck is high enough to need one.
- Get the finish included. An unoiled new deck greys within a season.
The short version
Get three written quotes on the same scope. The gap between the cheapest and the dearest is usually not profit, it is what each one left out. Use the ranges above to spot a quote that is too low to be finished properly.
Common questions
How much does a deck cost in Australia in 2026?
Treated pine decks run about 350 to 650 dollars per square metre, hardwood 550 to 950, and composite 600 to 1,100. A typical 25 square metre ground level pine deck is roughly 9,000 to 16,000 dollars.
Do I need council approval to build a deck in NSW?
Not always. Some low decks are exempt development, but height, size, distance to boundaries and bushfire or flood zoning all affect it. Confirm with your council before you buy materials, because removing a deck is far more expensive than getting approval first.
Is composite decking worth the extra cost?
If you will not maintain timber, yes. Composite costs more up front but removes the annual oiling, and over 15 years the saving in time and materials narrows the gap. In full sun it does get hot underfoot.
How long does a deck last?
A treated pine deck that is maintained lasts 15 to 25 years. Hardwood and quality composite commonly last 25 to 30 years. The frame and the footings decide the real lifespan, not the surface boards.