By the Sydney Timber Supply team
Short answer: both are legitimate decking choices, and the right one depends on your budget, the look you want and how long you need the deck to last. Merbau is an imported hardwood with supplier durability Class 2 above ground; it is stable, widely used and usually the cheaper option. Australian hardwoods such as Ironbark, Spotted Gum, Redgum, Gympie Messmate and Blackbutt are rated Class 1 above ground on supplier specification sheets, with distinctive grain and colour. Sydney Timber Supply stocks both, so this comparison has no side to take.
Merbau: the practical workhorse
Merbau is an imported hardwood and one of the most widely used decking timbers in Australia. Supplier documentation rates it Class 2 for above-ground durability. It is known for being stable in service, which is part of why it has been a fixture of Australian backyards for decades.
At Sydney Timber Supply, Merbau decking is listed in 90 x 19, 140 x 19, 190 x 19, 90 x 42 and 140 x 42 mm, sold per linear metre in random lengths. On price, Merbau usually comes in cheaper than the Australian hardwood range; check current listed prices in our Merbau collection.
One thing we will not do is call Merbau an Australian timber or a Class 1 timber, because it is neither. It does not need inflated claims: it is a stable, proven, widely used decking board at an accessible price.
Australian hardwoods: Class 1 durability and character
Our Australian hardwood range covers five species, all rated Class 1 above ground with 40+ year service life on supplier specification sheets:
- Ironbark: very hard and dense, in 86 x 19 mm, 135 x 19 mm and 135 x 35 mm (140 x 35 mm option)
- Spotted Gum: striking grain, same sizes as Ironbark
- Redgum (QLD Reds): rich red tones, same sizes
- Gympie Messmate (QLD Blondes): warm yellow-brown, 86 x 19 mm, 135 x 19 mm and 135 x 35 mm (140 x 35 mm option)
- Blackbutt: creamy blonde to honey tones, straight grain, 86 x 19 mm, 135 x 21 mm and 140 x 35 mm
Class 1 is the highest natural above-ground durability class for timber. The other thing the Australian species offer is character: each has a distinctive grain and colour, from the reds of Redgum to the blondes of Gympie Messmate and Blackbutt, rather than the fairly uniform look of Merbau.
Side by side
| Merbau | Australian hardwoods | |
|---|---|---|
| Origin | Imported | Australian |
| Durability (supplier-published, above ground) | Class 2 | Class 1, 40+ years |
| Character | Stable, consistent, widely used | Distinctive grain and colour per species |
| STS decking sizes | 90 x 19, 140 x 19, 190 x 19, 90 x 42 and 140 x 42 mm | 86 x 19 mm and 135 x 19 mm (Ironbark, Spotted Gum, Redgum and Gympie Messmate also in 135 x 35 mm; Blackbutt in 86 x 19, 135 x 21 and 140 x 35 mm) |
| Price positioning | Usually cheaper | Usually a premium over Merbau |
| How it is sold | Per LM, random lengths | Per LM, random lengths |
Both are sold per linear metre in random lengths, with preferred lengths by quote. For quantity calculations, assuming a 4 mm gap, a 90 mm Merbau board covers 94 mm, an 86 mm board covers 90 mm and a 135 mm board covers 139 mm. The gap you lay comes from the installation guide for your product. Our timber calculator converts your deck area to linear metres for any of these profiles.
When Merbau makes sense
- Budget is the deciding factor and you still want a genuine hardwood deck.
- You want a stable, well-understood board that trades and installers know inside out.
- You are matching or extending an existing Merbau deck.
When Australian hardwood makes sense
- You want the highest natural above-ground durability class (Class 1, 40+ years per supplier sheets).
- The look matters: you want the grain of Spotted Gum, the reds of Redgum or the blondes of Blackbutt and Gympie Messmate.
- You prefer Australian-grown timber. See Australian timber and certification for how we present those claims.
- Bushfire requirements are in play: Blackbutt, for example, is BAL 29 rated per the supplier flyer.
FAQ
Is Merbau an Australian timber?
No. Merbau is imported. Our Australian hardwood range is Ironbark, Spotted Gum, Redgum, Gympie Messmate and Blackbutt.
Is Class 2 durability bad?
No. Class 2 is a solid above-ground durability rating, and Merbau's track record in Australian decks speaks for itself. Class 1 is simply the higher class.
Which is cheaper?
Merbau is usually the cheaper option. We avoid quoting exact figures in articles because pricing changes; check the product pages in the decking collection for current listed prices.
Talk to us
Still weighing it up? We stock both ranges and are happy to talk through your job honestly. Collect from West Gosford by prior arrangement or arrange delivery, and for packs, preferred lengths or bulk pricing, request a quote or call 0440 137 068.
Technical details drawn from supplier specification sheets; reviewed 19 July 2026.