Key takeaways
- Treated pine $250-$400/m2, merbau $320-$520/m2, spotted gum/blackbutt $420-$650/m2 fitted
- The board is only part of the price - joist spacing, fixings and footings move it as much as the species
- Cheaper timber needs more maintenance, so the lifetime cost gap is smaller than the upfront gap
- Green (unseasoned) hardwood is a false economy - it cups and splits within 2 summers
See the full price table, try the deck cost calculator, or compare 3 itemised quotes.
Timber Decking Cost: the 2026 price table
Structured Adelaide pricing - the data no SERP competitor publishes.
| Deck type | Indicative range |
|---|---|
| Treated pine deck, fittedBudget option. Recoat every 12-18 months, softer surface. | $250-$400 / m2 |
| Merbau deck, fittedThe Adelaide default. Dense, stable, dark - tannin bleeds early. | $320-$520 / m2 |
| Spotted gum / blackbutt deck, fittedPremium Australian hardwood. Harder, better bushfire rating. | $420-$650 / m2 |
| Small timber deck (15-25 m2, ground level)Treated pine to merbau, no balustrade. | $6,500-$12,000 |
| Medium timber deck (25-50 m2, one stair set)Merbau or hardwood, one set of stairs, partial balustrade. | $12,000-$28,000 |
Indicative metro Adelaide ranges for 2026. Fitted, GST inclusive. Site conditions and balustrading move the figure.
What each timber species costs to own
Treated pine is the cheapest board, but it carries the highest maintenance: recoating every 12 to 18 months to hold colour, and a softer surface that marks. Merbau costs more upfront, is far more stable and durable, and needs oiling every 1 to 2 years. Spotted gum and blackbutt cost the most, are the hardest underfoot, hold colour longest and carry a better bushfire rating - which matters in the Adelaide Hills and Mitcham hills face.
The point is that the upfront price gap and the lifetime cost gap are not the same. A treated pine deck saves you money on day one and spends some of it back in recoating. A hardwood deck costs more on day one and asks for less over 15 years. Which is cheaper overall depends on how long you keep the home.
Why the board price is not the deck price
Supply-only timber is a fraction of a fitted price - merbau boards alone might be $70 to $120 per square metre against a fitted rate of $320 to $520. The gap is everything else: the frame, the footings, the fixings, the labour, the finish.
And those things vary between quotes. A cheap quote often hides a wider joist spacing that makes the deck bouncy, galvanised screws instead of 316 stainless, or fewer footings. The board species is visible in a quote; the framing decisions usually are not. Itemised quotes on the same scope are how you see them.
Decking Adelaide gets you 3 itemised timber quotes from BWC-licensed builders so the frame, boards, fixings, finish and balustrade are all separate lines you can compare.
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Timber Decking Cost - frequently asked questions
Fitted, in metro Adelaide for 2026: treated pine $250 to $400 per square metre, merbau $320 to $520, and spotted gum or blackbutt $420 to $650. The species is the biggest single driver, but joist spacing, fixings, footings and the finish all move the figure within and beyond those ranges.
It is worth it if you accept the maintenance. Treated pine is structurally sound and saves $100 to $250 per square metre over hardwood upfront. The trade-off is recoating every 12 to 18 months and a softer surface that dents. Over 15 years the lifetime cost gap with hardwood is smaller than the upfront gap, because the pine spends some saving back on recoating.
Green, unseasoned hardwood still holds construction moisture. As it dries out in Adelaide's climate it cups, twists and develops wide gaps - often within 2 summers - regardless of how well the deck was built. A small saving on the board buys a deck that looks poor in 2 years. Kiln-dried or properly seasoned timber is the only sensible choice.
A 30 square metre timber deck typically falls in the medium-deck band of $12,000 to $28,000, depending heavily on species, height and balustrading. In merbau at a mid-range fitted rate, with one set of stairs and a partial balustrade, expect somewhere around $15,000 to $22,000. Itemised quotes on your actual site set the real figure.
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