Everyone comparing timber, composite and treated pine wants the same thing: real numbers, not a vague "it depends" from a salesperson. So here they are. This is what timber decking actually costs in Canberra in 2026, broken down by material, what pushes the price up on a real block, and the costs that don't show up on the initial quote.
Average Cost Per Square Metre (Hardwood vs Treated Pine vs Composite)
Installed, treated pine decking typically runs $300–$400 per square metre, including materials, labour and basic council approval. Australian hardwoods like spotted gum and blackbutt sit higher at $450–$600 per square metre installed, reflecting materials that generally cost $200–$300 per square metre on their own versus $100–$150 for treated pine. Composite decking generally lands somewhere between the two on upfront price, trading a higher material cost than treated pine for close to zero ongoing maintenance spend over the life of the deck.
What Drives the Price Up (Slope, Height, Multi-Level, Council Fees)
The per-square-metre rate is only the starting point. A sloping block needs extra footings and framing to level out, and a genuinely steep block often calls for a multi-level design with connected platforms rather than one flat surface — more structure, more cost. Height matters too: once a deck sits above 1 metre off the ground, it generally needs a compliant balustrade and often additional engineering, both of which add to the total. And if your deck's height or distance from a boundary triggers a development application, council fees and processing time get added to the project on top of the build itself.
Sample Cost Breakdown for a 20m² and 40m² Deck
Working from the installed rates above, here's roughly what a straightforward, single-level deck costs at two common sizes:
- 20m² treated pine: approximately $6,000–$8,000
- 20m² hardwood: approximately $9,000–$12,000
- 40m² treated pine: approximately $12,000–$16,000
- 40m² hardwood: approximately $18,000–$24,000
These figures assume a relatively flat, easy-access block. Slope, height, multi-level design and any covered or balustraded sections will move the number — which is exactly why a site visit beats a phone estimate every time.
Hidden Costs People Forget (Engineering, DA Fees, Balustrades)
A few costs regularly catch people out because they're not part of the headline per-square-metre rate. Engineering certificates are often required for taller or multi-level decks. Development application fees apply if your design falls outside the exempt thresholds. Balustrades become a compliance requirement once a deck is elevated, adding a further cost per linear metre. And ongoing maintenance is a real, recurring cost too — hardwood decks need re-oiling roughly every 12–18 months at around $100–$150 in products, while treated pine needs re-staining every 2–3 years.
How to Get an Accurate Quote
A number over the phone is always a guess — an accurate quote needs someone to actually see the block, check the slope and soil, and confirm the material grade you want before pricing it. A proper quote should also state clearly whether council fees, engineering and balustrades are included or separate, so there's nothing left to discover after you've signed off. Our custom deck design and build process starts with exactly that kind of on-site assessment. If you want to see the full range of what's possible before you get a number, our timber decking page covers the species, features and design options we build across Canberra.
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