Deck cost in Australia, per square metre
Decks run $120–$450 per m² installed depending on material. But the subframe underneath costs roughly the same whatever boards you choose — and on a sloping block, the approval you didn't expect is the bigger surprise.
What a deck costs in Australia
Decking is quoted per square metre, and the installed rate covers three separate things: the boards you see, the subframe you don't, and the labour to put both together.
Installed pricing across Australia in 2026:
- Treated pine — roughly $120 to $250 per m², with metro quotes commonly landing above $200.
- Hardwood (merbau, spotted gum) — roughly $200 to $450 per m².
- Composite — roughly $250 to $450 per m², with premium boards and high-freight markets pushing beyond that.
Broken into components, boards alone run about $60 to $180 per m² for timber depending on species and grade, and $100 to $170 for composite. The subframe — joists, bearers and posts — adds roughly $40 to $80 per m² regardless of what you put on top of it.
That last figure is worth sitting with. The structure underneath costs about the same whether you're laying budget pine or premium composite, which means the cheaper your boards, the higher the proportion of your deck is invisible.
Boards, subframe, labour. A quote that shows them separately is a quote you can actually interrogate — and it's the only way to compare two builders who've specified different substructures. A single lump-sum per-square-metre figure hides the part of the deck that determines how long it lasts.
A real deck built without paying for labour
Keryn had a deck built at her Coffs Harbour home about five years ago. It came to roughly $7,000, and nothing about it cost more than she expected. It's one of the few jobs on her list she'd repeat without changing a thing.
The relevant detail: had friend and hubbie do work. No contracted labour.
We can't convert that into a per-square-metre figure because we don't have the deck's dimensions, and inventing one would be worse than leaving the gap. What it does illustrate is the shape of a deck budget when labour comes out of it. On a professionally built deck, labour is a substantial share of the total — on composite work, commonly around two-thirds. Take that out and what remains is boards, subframe timber, fixings and footings.
That's why decks are one of the more common genuine DIY projects in Australia. The materials are obtainable, the skills are learnable, and the saving is proportionally larger than on almost any other outdoor job.
The approval most people don't expect
A deck feels like landscaping. Structurally and legally, it often isn't.
Requirements vary by state and council, but you generally need approval where a deck is more than about a metre above ground, where it's attached to the dwelling, or where it exceeds a certain size. Building permit costs commonly run $200 to $800 on top of the build.
Height is the trigger people miss. A deck sitting just above ground level on a flat site is frequently exempt; the same deck on a sloping block, where one end is well clear of the ground, may not be. Elevated decks also need engineering for the posts and footings, and that engineering is not optional — it's what stops the structure moving.
If your block slopes, or the deck attaches to the house, check with your council before you order timber rather than after.
Timber versus composite, honestly
Composite costs more up front and eliminates the recurring cost. Timber costs less and doesn't.
A timber deck in Australian conditions needs oiling or staining periodically to survive UV and moisture — the ongoing figure commonly quoted is $300 to $800 a year for a typical deck, whether that's product and your weekend, or someone else's labour. Composite typically breaks even against timber somewhere around year five to seven.
Which is better depends less on the maths than on you. If you'll genuinely oil a timber deck every year or two, timber is warmer, cheaper and repairable board by board. If you know you won't, composite is the honest choice, because a neglected timber deck fails faster than an unmaintained composite one and looks worse doing it.
The one thing not to do is buy timber on the assumption you'll maintain it, and then not. That's the most expensive version of both options.
Frequently asked questions
How much does a deck cost per square metre in Australia?
Installed, roughly $120 to $250 per m² for treated pine, $200 to $450 for hardwood, and $250 to $450 for composite. Boards alone are $60 to $180 per m² for timber and $100 to $170 for composite, with the subframe adding $40 to $80 per m² on top.
Can I build a deck myself?
It's one of the more realistic DIY projects, and the saving is proportionally large because labour is a substantial share of a professional deck — on composite work commonly around two-thirds. One Coffs Harbour deck built with help from a friend and family came to around $7,000 with no contracted labour. Height and attachment to the house may still require approval and engineering regardless of who builds it.
Do I need council approval for a deck?
Often, and more often than people expect. Requirements vary by state and council, but approval is generally needed for decks more than about a metre above ground, decks attached to the dwelling, or decks over a certain size. Permits commonly cost $200 to $800. Sloping blocks are where this catches people out.
Is composite worth the extra cost?
It typically breaks even against timber around year five to seven, because it removes the recurring maintenance — commonly $300 to $800 a year for a timber deck. The honest test isn't the maths, it's whether you'll actually oil a timber deck on schedule. If you won't, composite is the better buy.
What should a deck quote include?
Boards, subframe and labour shown separately, plus footings, fixings, and any stairs or balustrades. The subframe costs roughly the same regardless of what boards go on top, so a quote that hides it is hiding the part that determines how long the deck lasts.
Sources & further reading
- First-hand figure contributed by Keryn, a homeowner in Coffs Harbour NSW: a deck built approximately five years ago for around $7,000, constructed with help from a friend and family rather than contracted labour. Deck dimensions were not recorded, so this figure cannot be converted to a per-square-metre rate.
- Australian per-square-metre pricing cross-checked against 2026 published pricing from Australian decking suppliers and installers, including Brite Decking, Property Blueprint Co and NexGEN Decking.
- Approval requirements for decks vary by state and local council. Confirm with your council before commencing work.
Cost ranges here are planning estimates that vary by region and home — see how we research and what our numbers mean, and always confirm with local, itemised quotes.