Composite decking cost in Australia

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What do Australian guides say a deck costs per square metre?

No board maker we checked publishes an AUD price, so the figures below are estimates from two cost guides, supply and install. Neither says whether GST is included.

What’s The Damage gives typical values of $260 for treated pine, $420 for merbau, $550 for mid-range composite and $570 for premium composite. The aluminium figure comes from a lifespan table, so read it as indicative only.

What sits on top of the per-metre rate?

What’s The Damage lists these as extras:

• Elevated or high-set deck: $50 to $180 per m². The Quote Yard says $50 to $120 above 600 mm.
• Balustrade: $150 to $450 per lineal metre.
• Steps: $180 to $400 per step, or $1,000 to $4,500 for a flight.
• Old deck removal: $20 to $55 per m².
• Pergola: $5,000 to $15,000.

The Quote Yard says balustrades, stairs, posts and termite management are normally additional to its rate.

Which prices should you be careful with?

Airtasker’s deck installation page, updated in April 2025, shows totals from $3,600 to $11,500 by deck size. Its older composite page, updated in December 2023, gives $100 to $300 per m² with a median of $180 and boards at about $10 to $22 each. That is well below the other guides and the page is stale, so we don’t rely on it.

What does timber cost by the metre?

Canterbury Timbers in Sydney lists Merbau 90 by 19 mm decking at $7.15 per metre in random lengths, from its shop feed on 30 October 2026. We haven’t confirmed whether that includes GST. On a 90 mm board with a 5 mm gap, that is roughly $75 per m² of boards before the frame, fixings and labour.

How do you get a price for your own deck?

Get at least two quotes with the same scope: boards, frame, footings, fixings, trims, stairs and balustrade. Then enter them in the decking cost calculator, which keeps the per-m² total for each. Board sizes and joist spacing are in the boards table, and merbau vs composite compares the materials.

Is composite decking more expensive over its life?

Up front, composite boards cost more than treated pine. RenoGuide, which isn’t a composite seller, gives board supply at $90 to $180 per m² for composite, $70 to $150 for hardwood and $40 to $90 for treated pine. It says timber re-oiling or resealing every one to two years costs about $300 to $1,000 plus, while composite mainly needs cleaning.

Sellers and installers go further, and their numbers carry a bias:

• Brite Decking, a composite seller, says composite pays back within 5 to 7 years and puts 20-year totals for a 30 m² deck at $6,900 to $12,900 for composite against $11,400 to $27,400 for timber.
• COEN, a composite maker, gives 10-year upkeep for a 40 m² deck at about $2,500 to $5,700 for treated pine and $3,200 to $6,200 for hardwood, against about $0 for composite.
• Landscaping Quotes in Adelaide says the 20-year cost is roughly even.
• SA Quality Home Improvements says composite lasts 25 to 30 years and timber 15 to 20, with oiling or staining every 12 to 18 months.

We found no independent lifecycle study. Run your own numbers: enter your quotes and a yearly timber upkeep figure in the cost calculator.