Published
The short answer
Bella Carpentry, an Unley deck builder, publishes $200 – $350 per m² for a new deck installed in pine, hardwood or composite. Paul’s Decking and Pergolas (Hectorville) publishes $3,000 – $5,000 for a small basic 10 m² treated pine or hardwood deck in its Elizabeth South price bracket, and $7,000 – $10,000 for a small hardwood or composite deck in its Unley bracket. Neither says whether GST is included (checked 28 October 2026). A low deck within SA’s exemption needs no PlanSA application, so it pays no PlanSA fees.
New deck prices in Adelaide
Two Adelaide deck builders publish deck prices, one per square metre and one per deck by suburb price bracket:
New deck prices from Adelaide deck builders
| Deck | Price | Source |
|---|---|---|
| New deck, per m² installed (pine, hardwood or composite) | $200 – $350 per m² | Bella Carpentry, Unley |
| Small basic deck, 10 m², treated pine or hardwood (Elizabeth South price bracket) | $3,000 – $5,000 | Paul’s Decking and Pergolas, Hectorville |
| Small deck, hardwood or composite (Unley price bracket) | $7,000 – $10,000 | Paul’s Decking and Pergolas, Hectorville |
| Large deck, 25–30 m², composite boards and built-in seating (Elizabeth South price bracket) | $12,000 – $18,000 | Paul’s Decking and Pergolas, Hectorville |
Published by two Adelaide deck builders, checked 28 October 2026: Bella Carpentry (undated page; “depending on the materials used, the complexity of the design, and site conditions”) and Paul’s Decking and Pergolas (24 July 2025, prices by suburb price bracket). Neither says whether GST is included. These are their published guides, not a quote: height, steps, access and the boards chosen set a deck’s own price.
By our arithmetic, a 20 m² deck at Bella Carpentry’s $200 – $350 per m² would be $4,000 – $7,000 (20 × $200 and 20 × $350), before steps or anything unusual about the site. That’s a guide to the order of cost, not a quote.
Deck prices by timber: treated pine, merbau, spotted gum and composite
No Adelaide deck builder we found publishes prices by board type, so these are a national cost guide’s figures, labelled national:
Deck prices per m² by decking board (national)
| Deck | Price | Source |
|---|---|---|
| Treated pine deck, per m² (low to high; typical $260) | $180 – $350 | What’s The Damage (national) |
| Merbau deck, per m² (typical $420) | $300 – $550 | What’s The Damage (national) |
| Spotted gum deck, per m² (typical $480) | $350 – $600 | What’s The Damage (national) |
| Composite deck, per m² (typical $550) | $280 – $700 | What’s The Damage (national) |
| Deck steps, per step (typical $300) | $180 – $400 | What’s The Damage (national) |
| Old deck demolition and removal, per m² (typical $35) | $20 – $55 | What’s The Damage (national) |
A national cost guide’s October 2026 figures, including GST, checked 28 October 2026. It publishes an “Adelaide” table too, but every row there is the national figure less 8%, so we show the national rows as national. The guide is paid by tradespeople for the enquiries it passes on.
What changes the price of a deck
Size and shape
Square metres drive the price, but levels, corners and cut-outs around trees or downpipes add cutting and framing time on top of a plain rectangle.
Height off the ground
A low deck needs short posts or adjustable steel stumps and little bracing. A higher floor needs more framing, and once any point of it is more than 500 mm above the natural ground, the deck needs PlanSA approval and its fees (below).
The boards
Treated pine, merbau, spotted gum or composite: the national figures above show the spread. Composite boards are fixed to the maker’s spacing and fastener rules, and the frame underneath is usually treated pine or steel whichever board goes on top.
Steps, landings and screens
Each step, landing or screen adds materials and time on top of the area rate, which is why the national guide prices steps separately.
Footings and the ground
Posts or stumps sit on concrete footings. Rock, fill, tree roots or a steep fall change how much digging and concrete each footing takes.
Access and the old deck
A back yard reached only through a narrow side gate means carrying every board by hand. Taking up an old deck is often its own line in a quote, and EPA SA says old CCA-treated posts must go to an EPA-authorised landfill, never burnt or buried.
Deck sanding and oiling prices
Sanding and re-oiling a sound deck is priced per square metre:
Deck sanding, oiling and refinishing prices
| Work | Price | Source |
|---|---|---|
| Deck sanding and refinishing, per m² | $50 – $100 per m² | Stain And Seal, Goodwood |
| Deck sanding and oiling, per m² (typical $40) | $25 – $60 | What’s The Damage (national) |
Stain And Seal’s figure (“depending on the condition of the timber, existing coating, access”) is from its Adelaide service page, updated 25 August 2026, with no GST statement. The national guide’s October 2026 figure includes GST. Checked 28 October 2026.
Split boards and loose steps are repairs priced on top, and rotten joists or bearers that carry the deck are structural work. See deck repairs and oiling.
PlanSA fees when a deck needs approval
A deck needs no approval if no point of its floor is more than 500 mm above the natural ground and no part is within 900 mm of a boundary, unless it’s in a bushfire-prone area, the Historic Area Overlay or a heritage place (the approval guide has the details). Outside those limits, PlanSA’s fees apply:
PlanSA fees for a deck that needs approval
| Fee | Price | Source |
|---|---|---|
| Lodgement fee, total development cost up to $10,000 | $98.50 | PlanSA |
| Lodgement fee, over $10,000 up to $50,000 | $158 | PlanSA |
| Building assessment, Class 10 (such as a verandah, carport or shed) | $154 or 0.25% of the development cost, whichever is greater | PlanSA |
| Planning consent, deemed-to-satisfy, up to $10,000 / over $10,000 | $151 / $250 | PlanSA |
| Class 10 compliance fee, over $10,000 / under $10,000 | $95.50 / $0 | PlanSA |
PlanSA’s “Fees and charges at a glance – July 2026”, checked 28 October 2026. Which fees apply depends on whether the job needs planning consent, building consent or both, and councils or private certifiers may charge their own fees. Fees are indexed each 1 July.
By our arithmetic, an $8,000 deck that needs building consent only would pay $98.50 + $154 + $0 = $252.50 at the July 2026 fees, or $403.50 if it also needs deemed-to-satisfy planning consent ($151), before any council or certifier charges.
Getting a deck quoted in Adelaide
- The rough size, and photos of where the deck will go
- How high the floor will sit above the ground at its highest point
- How close the deck comes to the nearest boundary
- The boards you’d like, and any steps, landing or screen
- Whether an old deck comes up first, and how the back yard is reached
Licensed Adelaide deck builders quote from these details. A deck contract of $20,000 or more must be in writing with the builder’s licence number, and the deposit can be no more than 5%: see how to check a builder’s licence in SA.
Questions about deck cost
Do Adelaide deck prices include GST?
Bella Carpentry and Paul’s Decking and Pergolas don’t say whether their published prices include GST. The national guide’s figures include it (October 2026, checked 28 October 2026). Ask for GST to be shown on any quote.
Is composite decking dearer than hardwood?
On the national guide’s typical figures, yes: $550 per m² for composite against $420 for merbau and $480 for spotted gum, with treated pine lowest at $260 (October 2026, including GST). Composite needs no oiling, which the up-front price doesn’t show.
What size deck can I build without approval?
SA’s deck exemption doesn’t set a floor area. Its tests are height (no point of the floor more than 500 mm above the natural ground) and position (no part within 900 mm of a boundary), outside bushfire-prone areas, the Historic Area Overlay and heritage places.
Can a deck be split into stages to stay under $20,000?
Not for the contract rules. Section 3(2) of the Building Work Contractors Act treats domestic building work done in stages at one site under separate contracts as a single contract, so the written-contract, deposit and cooling-off rules still apply.
Does a deck in the Adelaide Hills cost more?
It can. In a bushfire-prone area the deck exemption doesn’t apply, so the deck needs approval and its fees, and MBS 008 sets a Bushfire Attack Level for the site, which the design has to meet.
How much does it cost to replace a few deck boards?
Board replacement is priced once the deck has been seen, because it depends on how many boards have gone and whether the joists under them are sound. Photos of the worst boards and underneath help. See deck repairs and oiling.
Where these figures come from
The prices and rules on this page come from these published pages, checked on 28 October 2026.
- Bella Carpentry: decking Adelaide (FAQ) · Unley carpentry business, service page, undated
- Paul’s Decking and Pergolas: what a new deck means for property value in Adelaide · Hectorville deck and pergola builder, blog post, 24 July 2025
- What’s The Damage: decking cost 2026 · National cost guide (paid by tradespeople for enquiries), updated October 2026, prices include GST
- Stain And Seal: deck sanding in Adelaide · Goodwood deck restoration business, service page, updated 25 August 2026
- PlanSA: fees and charges at a glance, July 2026 · SA Government (Department for Housing and Urban Development), fee schedule from 1 July 2026
- Planning, Development and Infrastructure (General) Regulations 2017, Schedule 4 · South Australian regulations: Schedule 4 cl 4 (exempt decks, pergolas, fences, sheds, retaining walls)
- PlanSA: why you need approval · SA Government planning portal guidance, with the approval wizard
- Building Work Contractors Act 1995 (SA) · South Australian legislation: ss 3, 6, 28–36, 47A–47D, 49 and 50
- EPA SA: CCA treated timber · Environment Protection Authority South Australia, modified 25 September 2026
- Ministerial Building Standard MBS 008: designated bushfire prone areas · SA Government ministerial building standard, July 2020
- CBS: working as a builder in SA · SA Government, Consumer and Business Services factsheet, version 3.0, November 2025
