How much does a 20 sqm deck cost in Australia?

A 20 sqm deck in Australia costs approximately $5,500–$11,000 depending on timber type, site conditions, and whether steps or balustrades are needed.

Is composite decking worth the extra cost?

Composite decking ($280–$550/sqm in Australia) costs slightly more than merbau but requires virtually no maintenance. Over 10 years, it's often cheaper than hardwood when you factor in oiling costs.

How long does it take to build a deck in Australia?

A standard deck (15–25 sqm) in Australia takes 3–7 days to build. Larger or more complex decks with pergolas, steps, and balustrades can take 2–3 weeks.

Cost Guide

Decking Cost Australia 2026

Q: How much does decking cost per sqm in Australia?

Decking in Australia costs $180–$350/sqm for treated pine, $300–$550/sqm for merbau hardwood, and $280–$550/sqm for composite — all supply and installation including subframe.

Q: Do I need a permit for a deck?

In most Australia councils, decks under a certain height (usually 500mm–1m) and size don't need a permit. Higher or larger decks typically require a building permit. Always check with your local council before starting.

Q: How long does a timber deck last?

Treated pine decks last 15–20 years with regular maintenance. Hardwood (merbau, spotted gum) lasts 25–40+ years. Composite decking lasts 25–30 years with minimal maintenance.

Decking costs depend on the timber type, deck size, height, and whether steps or balustrades are needed.

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National Pricing Overview

Service	Low	Typical	High
Treated pine deck (per sqm)	$180/sqm	$260	$350
Hardwood deck — merbau (per sqm)	$300/sqm	$420	$550
Hardwood deck — spotted gum (per sqm)	$350/sqm	$480	$600
Composite deck (per sqm)	$280/sqm	$400	$550
Small deck (15 sqm, hardwood)	$5,000total	$7,500	$10,000
Medium deck (25 sqm, hardwood)	$8,000total	$12,000	$16,000
Large deck (40 sqm, hardwood)	$13,000total	$19,000	$26,000
Deck steps (per step)	$150/step	$250	$400
Deck balustrade / railing (per lm)	$120/lm	$200	$350
Deck sanding + oiling (per sqm)	$25/sqm	$40	$60
Old deck demolition + removal	$20/sqm	$35	$55
Pergola over deck (basic)	$5,000total	$8,000	$15,000

Prices verified February 2026 · Cross-referenced against 90+ Australian trade pricing sources · See methodology

National average prices. Select a city above for location-specific pricing.

Decking in Australia costs $180–$350/sqm for treated pine, $300–$550/sqm for merbau hardwood, and $280–$550/sqm for composite decking (all supply and installation). A medium 25 sqm deck costs $8,000–$16,000 depending on the material and complexity.

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What Affects Decking Costs in Australia

Timber type

Treated pine ($180–$350/sqm in Australia) is cheapest but needs regular oiling. Merbau ($300–$550/sqm) and spotted gum are premium hardwoods. Composite ($280–$550/sqm) is low-maintenance.

Deck size

A small 15 sqm deck in Australia costs $5,000–$10,000. Medium 25 sqm is $8,000–$16,000. Large 40 sqm decks run $13,000–$26,000. Larger decks get slightly better per-sqm rates.

Height & subframe

Ground-level decks in Australia are simplest. Elevated decks (over 1m) need substantial substructure, posts, and often engineering — increasing costs significantly.

Steps & balustrades

Steps cost $150–$400 per step in Australia. Balustrades/railings add $120–$350/lm. These are required by code for any deck over 1m above ground.

Site access & slope

A flat, accessible Australia backyard is cheapest. Sloping sites, difficult access, or existing structures to build around all increase labour time and cost.

Maintenance requirements

Hardwood decks need oiling 1–2 times per year (DIY $50–$100, professional $25–$60/sqm in Australia). Composite decking needs almost no maintenance — a hose-down is usually sufficient.

How to Save Money on Decking in Australia

Get 3 quotes from licensed Australia deck builders — make sure each quote includes the same timber species and subframe specifications

Consider composite decking if low maintenance is a priority — it costs similar to hardwood upfront but saves on annual oiling

Check your Australia council for permit requirements — decks over a certain height or size may need a building permit

Ask about the subframe — a quality subframe (often the biggest cost component) determines how long the deck lasts

Factor in ongoing maintenance costs — a hardwood deck in Australia costs $200–$500/year to maintain; composite costs almost nothing

Ask about drainage under the deck and how the structure connects to your house — waterproofing the connection point is critical

Frequently Asked Questions

How much does decking cost per sqm in Australia?

Treated pine $180–$350/sqm, merbau hardwood $300–$550/sqm, spotted gum $350–$600/sqm, composite $280–$550/sqm — all supply and installation.

Is composite decking worth it?

Composite costs similar to hardwood upfront but needs virtually no maintenance. Over 10 years it's often cheaper total when you factor in annual oiling costs.

Do I need a permit for a deck?

Decks under a certain height (usually 500mm–1m) and size usually don't. Higher or larger decks typically need a building permit. Check with your local council.

How long does a timber deck last?

Treated pine 15–20 years. Hardwood 25–40+ years. Composite 25–30 years. All with appropriate maintenance.

How long does it take to build a deck?

A standard 15–25 sqm deck takes 3–7 days. Larger or complex decks with pergolas, steps, and balustrades take 2–3 weeks.