As of October 2026, What's The Damage prices composite decking in Sydney at $320 to $805 per square metre installed, typically $630, against $205 to $400 for treated pine, $345 to $630 for merbau and $400 to $690 for spotted gum. Composite costs about the same as hardwood up front but needs no oiling, while timber is usually oiled every one to two years. hipages' national guide is lower, at about $350 per m² for composite and from $320 per m² for hardwood (January 2026).
- Sydney installed prices (What's The Damage, October 2026): composite $320 to $805 per m²; treated pine $205 to $400; merbau $345 to $630; spotted gum $400 to $690.
- Premium capped composite costs $520 to $1,025 per m² in Sydney, according to the same guide.
- Hardwood decks are usually oiled every 1 to 2 years; composite needs washing but no oiling or sanding.
- What's The Damage says composite can be 15 to 20°C hotter than timber in direct summer sun; lighter colours run cooler.
- On NSW bushfire prone land, an exempt deck within 5 m of the house must be non-combustible, so check your BAL and the product's test results first.
How much does composite decking cost in Sydney?
Composite decking in Sydney typically costs about $320 to $805 per square metre installed, with a typical price of $630, according to What's The Damage (verified October 2026). Premium capped or solid-core boards cost more, at $520 to $1,025 per m².
Those prices include the frame of posts, bearers and joists as well as the boards. The frame is much the same for every board type, so the board choice drives most of the difference.
Other guides give lower figures. hipages' national guide lists composite at about $350 per m², hardwood from about $320 per m² and treated pine at about $200 per m² (January 2026). What's The Damage's national guide puts composite at $280 to $700 per m². Sydney labour and access costs explain part of the gap.
Composite decking is made from a blend of wood fibre and plastic. Capped composite has an extra plastic shell that resists stains and fading.
Timber vs composite decking compared
This table compares the main choices for a Sydney deck. Treat lifespans as typical ranges, not guarantees.
| Factor | Treated pine | Merbau / spotted gum | Composite |
|---|---|---|---|
| Installed cost per m² (Sydney) | $205 to $400 | Merbau $345 to $630; spotted gum $400 to $690 | $320 to $805 (premium capped $520 to $1,025) |
| Typical lifespan | 15 to 20 years | Merbau 25 to 40 years; spotted gum 30 to 50 years | 25 to 30 years |
| Maintenance | Stain or oil every 1 to 2 years | Oil every 1 to 2 years | Wash down; no oiling or sanding |
| Heat in summer sun | Cooler underfoot | Cooler underfoot | Can be 15 to 20°C hotter than timber; lighter colours cooler |
| Bushfire prone land | Depends on your BAL | Some hardwoods suit certain BALs; check | Only products tested for your BAL |
| Slip resistance | Depends on profile and finish | Depends on profile and finish | Depends on profile; ask for a test rating |
| Product warranty | Ask the supplier | Ask the supplier | 25 to 30 years from reputable brands |
Costs: What's The Damage Sydney decking guide (October 2026). Lifespan and maintenance: What's The Damage national decking guide. Heat and warranty: What's The Damage timber vs composite guide. Bushfire and slip: check the product and your site.
Which costs less over 20 years?
Composite often costs more to build but less to keep. What's The Damage's worked example for a 40m² deck over 20 years puts hardwood at $21,000 to $34,900 all up, including oiling, sanding and board replacement. It puts capped composite at $16,100 to $22,200, mostly the build cost.
Your result depends on how often you would really oil the deck, and whether you pay someone to do it. What's The Damage lists a Sydney re-oil (clean and two coats) at $17 to $52 per m² and a full sand and oil at $29 to $69 per m².
If you plan to sell within a few years, or the deck is shaded and little used, the lower build cost of timber may matter more.
Remember that the frame lasts only as long as its weakest part. Sydney's humid summers, termites and poor airflow under low decks shorten the life of any deck. Ask how the frame will be treated, ventilated and fixed, not just which boards go on top.
Merbau vs spotted gum: which hardwood suits Sydney?
Both are popular, and both cost less than many premium composites. What's The Damage prices spotted gum at $400 to $690 per m² and merbau at $345 to $630 per m² in Sydney.
- Spotted gum: a NSW native hardwood. What's The Damage describes it as naturally durable (Class 1 above ground), termite-resistant and now Sydney's most popular premium decking timber.
- Merbau: an imported hardwood with a deep red-brown colour. It is known to leach tannins when new, which can stain paving or concrete below, so ask your builder how they manage this.
- Blackbutt: another NSW hardwood, priced at $380 to $715 per m² in Sydney.
- Treated pine: the cheapest board at $205 to $400 per m². What's The Damage notes it needs regular oiling to stop greying and surface cracking, and should be at least H3 treated for outdoor decking.
Whichever timber you choose, ask for timber from a supplier that can show where it came from.
Does composite decking get hot?
Yes, it can. What's The Damage says composite surfaces can be 15 to 20°C hotter than timber in direct summer sun, and that light colours run cooler than dark ones.
This matters for north- and west-facing decks and pool surrounds where people walk barefoot. Western Sydney is regularly 5 to 8°C warmer than the coast in summer, the same guide notes. Shade from a pergola, a lighter board colour or timber may suit these spots better.
Which decking is best for bushfire-prone land?
It depends on your Bushfire Attack Level (BAL), which measures how exposed your home is to ember attack, radiant heat and flame. Construction requirements rise with the BAL under the Australian Standard AS 3959.
For an exempt deck in NSW, the rules are simple: on bushfire prone land, a deck less than 5 metres from the house must be built of non-combustible material. Decks that need a CDC or DA must meet the BAL requirements set for your site.
Check whether your land is mapped as bush fire prone before you choose a board. Use the NSW RFS online tool or the Planning Portal property search, then ask your builder for the product's bushfire test certificate for your BAL. Do not rely on a sales brochure.
Parts of Sydney with bushfire mapping include areas around Ku-ring-gai, Pittwater and parts of the Sutherland Shire, What's The Damage notes.
Is composite or timber decking more slip resistant?
Neither is always better. Slip resistance depends on the board profile, surface texture, coating and how clean and wet the deck is.
For pool surrounds and outdoor stairs, ask for the board's slip-resistance test rating to the Australian Standard AS 4586, and compare like with like. Keep decks clean of moss, algae and leaves, which make any surface slippery.
What's The Damage notes that some composite brands offer slip-resistant profiles for pool surrounds, and that composite will not splinter.
How much does a covered deck cost?
Add the cost of a roof to the deck. What's The Damage prices a basic timber or aluminium pergola over a Sydney deck, about 4 x 4 m to 4 x 6 m, at $5,750 to $17,250 (typical $9,200). A medium 25m² hardwood deck costs $9,200 to $18,400 in the same guide.
A roofed deck has extra approval rules. See our guides Pergola Cost Sydney and Do You Need Council Approval for a Pergola in NSW?
Does your new deck need council approval?
Many low decks are exempt in NSW if they are no more than 25m², have a floor no more than 1 metre above ground, sit behind the building line and are at least 900mm from each boundary in most zones. The board material does not change these limits. Our guide Do I Need Council Approval for a Deck in NSW? has the full checklist.
Questions to ask your deck builder
- Which board do you recommend for my sun, shade and use, and why?
- Is the price per m² for the full deck, including frame, fixings and finishing?
- What joist spacing and fixings does the board maker require?
- What is your contractor licence number? (A licence is needed for residential building work over $5,000 including GST, and work over $20,000 needs Home Building Compensation cover.)
- What warranty applies to the boards and to your workmanship?
Get your deck quoted
Describe your deck job to MyTradeCrew. Tell us the size, height off the ground, the boards you are considering and whether you need stairs or a balustrade. We will send it to up to three vetted, licensed and insured local deck builders from our crew, who can compare timber and composite for your site and give you a written quote.
Frequently asked questions
What is the best decking timber in Australia?
There is no single best timber. In Sydney, spotted gum is popular for durability and colour, merbau is a common lower-cost hardwood, and treated pine is the budget choice. Choose based on your budget, sun exposure, bushfire rating and how much oiling you will do.
How long does composite decking last?
What's The Damage gives a typical lifespan of 25 to 30 years for mid-range composite, and says reputable brands offer warranties of 25 to 30 years. Lifespan still depends on the frame under it, drainage, ventilation and following the maker's installation rules.
Is composite decking more expensive than timber?
It costs more than treated pine and about the same as hardwood per m² in Sydney, according to What's The Damage (October 2026). Composite saves on oiling and sanding over the years, which can make it cheaper over 20 years.
Does composite decking need oiling?
No. Composite does not need oiling, sanding or staining. It needs regular washing to remove dirt, leaves and mould. Timber decks are usually oiled every one to two years to protect the surface and colour.
Can composite boards go on an old timber deck frame?
Sometimes, if the frame is sound and the joist spacing, height and ventilation meet the composite maker's rules. Many composite boards need closer joists than timber. Ask your builder to inspect the frame before you decide.
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