Key takeaways
- Modwood / mid-tier composite $480-$720/m2, Trex / premium $620-$920/m2 fitted (Adelaide, 2026)
- Composite costs 40-80 percent more upfront than a merbau deck of the same size
- Trex typically costs $100-$200/m2 more than Modwood for the longer fade-and-stain warranty
- The maintenance saving is real, but whether it pays back depends on how long you keep the home
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Composite Decking Cost: the 2026 price table
Structured Adelaide pricing - the data no SERP competitor publishes.
| Deck type | Indicative range |
|---|---|
| Modwood / mid-tier composite, fittedAustralian-made, widely stocked, capped mid-tier board. | $480-$720 / m2 |
| Trex / premium capped composite, fittedPremium board, longest fade-and-stain warranty, wider colour range. | $620-$920 / m2 |
| Medium composite deck (25-50 m2)Capped composite, the maintenance-light family deck at a premium. | $18,000-$38,000 |
| Composite pool deck (40-60 m2)Pool-rated balustrade and slip-rated surface add to the composite base. | $30,000-$58,000 |
Indicative metro Adelaide ranges for 2026. Fitted, GST inclusive. Brand, capping grade and substructure move the figure.
Modwood vs Trex - the cost gap explained
Modwood is the Australian-made mid-tier name most Adelaide builders carry; Trex is the premium US brand. Fitted, Trex typically costs $100 to $200 per square metre more than Modwood. What you buy for that gap is a longer fade-and-stain warranty, a wider colour range, and a board many consider more refined.
Both are capped composites - co-extruded with a hard polymer shell that resists fade, scratches and stains far better than first-generation uncapped boards. Neither needs oiling or staining. The right choice depends on budget, colour preference and how much sun the deck takes. Our Modwood vs Trex guide compares them feature by feature.
Does composite pay back its premium?
Composite costs 40 to 80 percent more than a merbau deck of the same size. The argument for it is the lifetime maintenance saving: no oiling, no staining, no sanding - just an occasional wash. Over 15 to 20 years, a timber deck oiled annually accumulates real cost in product and labour or your own weekends.
Whether composite pays that back depends on how long you keep the home. If you are staying 15-plus years, the maintenance saving and consistent colour build a genuine case. If you might move in 5 years, you are paying the full premium upfront and capturing little of the saving - a timber deck may be the better financial call.
One more honest factor: dark composite gets hot in Adelaide summers, 60 to 70 degrees in direct sun. Decking Adelaide gets you 3 itemised composite quotes from BWC-licensed builders, and a builder who knows the boards will steer you to a lighter colour for any barefoot area.
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Composite Decking Cost - frequently asked questions
Fitted, in metro Adelaide for 2026: Modwood and mid-tier composite $480 to $720 per square metre, and Trex and premium capped composite $620 to $920. A medium 25 to 50 square metre composite deck runs $18,000 to $38,000. That is 40 to 80 percent more than a merbau deck of the same size.
Yes. Fitted, Trex typically costs $100 to $200 per square metre more than Modwood. The premium buys a longer fade-and-stain warranty, a wider colour range and a board many consider more refined. Both are capped composites that never need oiling. Our Modwood vs Trex guide compares them in detail.
Over the long term it can. Composite never needs oiling, staining or sanding, which saves real product and labour cost over 15 to 20 years against a timber deck. But composite costs 40 to 80 percent more upfront. Whether it pays back depends on how long you keep the home - staying long captures the saving, moving soon does not.
The composite board itself is far more expensive to manufacture than a timber board. Capping - the co-extruded polymer shell - adds further cost. You are paying upfront for a board that needs no oiling and holds consistent colour. The maintenance saving is the trade, but it only pays back over a long ownership.
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