Is Merbau a Hardwood? Properties, Uses and Buying Considerations

Is your old deck cracked, warped, or looking tired after one too many Australian summers? Are you looking for a timber that holds up outdoors without becoming a maintenance headache?

That is usually when people start comparing new timber options, and merbau tends to come up quickly in that search.

If merbau keeps popping up on your shortlist, you have probably also wondered whether it is even a hardwood, or just a name thrown around in decking ads. Let’s clear that up and walk through everything else worth knowing before you order a single board.

What Is Merbau Timber and What Does It Look Like?

Merbau is a tough tropical hardwood from the Intsia genus. Aussie builders and landscapers have used it for years because it stands up to the weather on its own, with no chemical treatment needed as you’d usually put on softwood.

Straight off the mill, it’s a yellowish brown. Give it some time outside in the sun and rain, and it deepens into a richer brown. There’s a bit of wave or interlock in the grain too, so boards don’t all look the same, which is part of the appeal if you’re after something with a bit more character than a dead flat surface.

Most of it comes kiln-dried, which improves strength and helps keep it stable. You get a reeded face on one side for extra grip, and a smooth one on the other if you want something cleaner underfoot. Lay it either way, and if you get sick of the look down the line, you can always flip it.

Why Is Merbau Used for Decking?

Ask any decking installer why merbau keeps coming up on quote requests. It usually comes down to a mix of looks and practicality.

• It is dense and hardwearing. So, it copes well with everyday foot traffic, furniture and outdoor use.
• The kiln-dried process improves stability, which helps reduce excessive movement once it is installed.
• It comes with a dual-finish profile (reeded and smooth). It gives flexibility in how the deck looks and feels underfoot.
• The colour deepens naturally with age. That is why many homeowners prefer this over timber, which fades or greys unevenly.
• It is widely available in Australia, with established supply chains and various board lengths to suit different deck sizes.

Advantages of Merbau Timber

Beyond decking specifically, merbau has a handful of properties that make it a practical, if not flawless, choice for outdoor timber work.

• Density and strength – Solid enough to cope with above-ground outdoor use and the everyday knocks that come with it.
• Dimensional stability – Kiln drying reduces shrinkage and warping compared to untreated timber.
• Natural appearance – The wavy grain and warm brown tones work whether you’re going for something modern or a bit more traditional.
• Workability – It can be cut, drilled and fixed using standard trade tools and techniques.
• Local familiarity – Tradespeople across Australia are well versed in installing and finishing it, so sourcing advice and installation know-how are easy to come by.

Possible Disadvantages of Merbau

It would not be a balanced brief without covering where merbau falls short, because no outdoor timber is without trade-offs.

• Tannin bleed – Freshly laid or newly wet boards can release tannins that stain surrounding surfaces.
• Ongoing maintenance – It still needs periodic coating to hold its colour and condition. It is not a set-and-forget product.
• Weight – Its density makes it heavier to handle and install than softer timbers.
• Cost – It typically costs more upfront than treated pine, though the comparison depends on your project scope.
• Not for ground contact – Merbau decking is designed for above-ground external use, not buried or ground-contact applications.

What Is Merbau Tannin Bleed?

We get asked this one a lot, and it is fair enough. Merbau naturally contains tannins, the same compounds that you would find in tea or red wine.

When new boards get wet, especially through those first few bouts of rain after they are laid, the tannins can leach out and leave reddish-brown staining on whatever is underneath or nearby: light-coloured pavers, pool coping, rendered walls, that sort of thing.

It is not a defect. It is just how the timber behaves early on. It typically settles down once the boards have weathered for a while.

If your project sits near a pool, light stone, or a colour you want to protect, it is worth planning ahead. You can stage the wash-off to protect adjacent surfaces during the first few weeks, or ask our team about sequencing your build to manage it.

Merbau vs Treated Pine

This comparison comes up constantly, especially for homeowners weighing cost against long-term appearance. Here is how the two generally stack up as decking materials.

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Feature	Merbau(Hardwood)	Treated Pine
Timber Type	Hardwood	Softwood, chemically treated
Natural Colour	Yellow-brown, darkens with age	Pale, often stays lighter unless stained
Density	Dense and heavy	Lighter and easier to handle
Durability Outdoors	Naturally suited to above-ground external use	Relies on chemical treatment for outdoor durability
Maintenance	Needs periodic oiling to maintain colour and condition	Also benefits from staining or sealing over time
Tannin Bleed	Yes, particularly when new	Not applicable
Typical Upfront Cost	Higher	Generally lower
Common Uses	Decking, verandahs, pool surrounds.	Framing, structural work, sleepers, fencing.

Picture a homeowner in outer Melbourne planning a new backyard deck. They have quotes for both merbau and treated pine sitting on the kitchen table. Treated pine looks like the cheaper option upfront. But they want that richer, warmer colour that only deepens with age. Also, they aren’t fussed about oiling a deck every so often.

A lot of people end up going with merbau for the decking boards you actually see, and treated pine underneath for the substructure nobody’s ever going to look at. It’s a pretty common way to do it, and worth bringing up with your supplier when you’re sorting out materials.

Is Merbau Suitable for Outdoor Use?

Yes, merbau decking is built for above-ground external applications. This includes decks, pool surrounds, verandahs, balconies and terraces. It is not designed for ground contact.

If part of your project involves posts or structural elements going into the soil, then that is a job for a different product, such as treated pine. For the visible, walked-on surfaces of an outdoor space, merbau is a proven and common choice across Australian builds.

Other Common Uses of Merbau

Decking gets most of the attention, but merbau also turns up in:

• Garden walkways and pathways
• Outdoor entertaining areas and pergola decking
• Commercial landscaping projects
• Balconies and terraces on residential and commercial builds

Does Merbau Need Maintenance?

Yes. Even pre-oiled merbau still needs a top coat once it is installed. Ongoing recoating is part of owning a merbau deck long term. Skipping this does not mean the timber will fail overnight, but it will affect the colour and surface over the years.

If you want the deck to keep looking the way it did on day one, budget for periodic maintenance rather than treating it as a one-and-done job.

What to Check Before Buying Merbau?

Before placing an order, it is worth confirming a few things with whoever you are buying from:

• Board size and profile, width, thickness, reeded or smooth face
• Whether it’s kiln-dried, and to what standard
• What length options are on offer, since merbau often ships in random lengths
• Documentation backing up where the timber came from
• Whether boards arrive pre-oiled, and what finishing you’ll still need to do yourself.

If you are not sure which of these apply to your project. Then get in touch with our team. We can walk through your layout, site conditions, and board specs before you place an order.

Final Summary

So, is merbau a hardwood? Yes. It’s earned its spot in Australian decks, verandahs and pool surrounds through a mix of durability, good looks and decades of trades knowing exactly how to work with it. It’s not maintenance-free.

It will bleed tannins in the early weeks, and it costs more than treated pine, but for anyone after a timber that actually looks better with age, it’s held up as a solid choice for a long time.

Planning a new deck or outdoor project? Explore Timber Central’s available Merbau decking products or contact the team to confirm current sizes, specifications and availability.

FAQs

Is Merbau a hardwood or softwood?

Merbau is a hardwood, sourced from broadleaf tree species rather than coniferous softwood species.

Is Merbau good for decking?

It is one of the most common decking timbers in Australia, mainly because of its density, durability, and the way it darkens with age. It does need upkeep, though, so expect that.

Is Merbau naturally termite-resistant?

It has some natural resistance thanks to its density and oils, but “resistant” isn’t the same as immune. Get the surrounding structural timber treated properly too.

Does Merbau bleed tannins?

Yes, especially in the first few weeks when boards are new and wet. It can stain pavers or light stone nearby, and it usually settles down once the timber’s had a chance to weather.

Does Merbau need to be sealed or oiled?

Yes, even the pre-oiled stuff. Plan on recoating every so often to keep the colour and surface in good shape.

Does Merbau turn grey?

Left alone, most outdoor timbers will eventually silver off in the sun. Keep up with oiling, and merbau holds its brown tones a lot longer.

Is Merbau stronger than treated pine?

It’s denser and heavier, being a hardwood against a softwood, but “stronger” really comes down to what you’re using it for. Worth checking against your actual application rather than assuming.

Is all Merbau sustainably sourced?

No. It depends on where it came from and who supplied it, so ask for proof of legal harvest and chain of custody before you buy.