If you’ve ever admired a rich, reddish-brown deck that seems to glow in the sun, there’s a good chance you were looking at Merbau wood. Known for its incredible strength, stability, and natural luster, Merbau has become one of the most sought-after hardwoods for both outdoor and indoor projects.
But what is the story behind this exotic timber? Why do professionals in construction and design and also homeowners, refer to it as the best ?
What point to consider if choosing Merbau for your home or deck? We will look at the characteristics, benefits and drawbacks, and the correct use of Merbau wood in order to assist you in figuring out whether it will be good for your next project.
🌳 What Is Merbau Wood?
Merbau, scientifically known as Intsia palembanica (and related species), is a tropical hardwood that grows mainly in Southeast Asia, Papua New Guinea, the Pacific Islands, and parts of northern Australia.
You may also know it as Kwila, Ipil or even Johnstone River Teak — all refers to the same dense and beautiful wood that has become a prime choice for flooring, decking and fine furniture.
Fresh Merbau has a yellowish to orangish brown color, while its colour deepens significantly when aged from new (fresh) to dark brown. The grain is generally interlocked or wavy and provides a distinctive appearance with a beautiful warm look and finish. With a rough yet consistent grain, Merbau looks and feels exactly like high-end hardwood — because it is.
⚖️ Physical & Mechanical Properties: Why Builders Love It
Merbau excels in performance as well. It isn’t just pretty — it’s built like a tank.
✅ Density and Hardness
Merbau is a heavy and dense hardwood, with a seasoned density of about 850–860 kg/m³ (and up to 1,150 kg/m³ unseasoned). This makes it far denser than most common timbers used in construction.
On the Janka hardness scale, it scores around 8.5 kN, meaning it can resist the denting and wear and it is also ideal for high-traffic flooring or outdoor decks.
✅ Strength and Stability
In terms of structural strength, Merbau truly stands out:
- Modulus of Rupture (MOR): ~147 MPa (seasoned)
- Modulus of Elasticity (MOE): ~18 GPa
- Crushing Strength: ~82 MPa
These numbers translate to a wood that can handle heavy loads, constant foot traffic, and harsh weather conditions without warping or cracking easily.
✅ Dimensional Stability
Merbau’s shrinkage rates are low — about 1.2% radial and 2.5% tangential from unseasoned to dry. This means it doesn’t expand or contract much with changes in humidity, making it a stable choice for both interior and exterior applications.
🧱 Durability and Resistance
Merbau wood is naturally durable and long-lasting, even without chemical treatments.
- Durability class (above ground): Class 1 — meaning it can last 60+ years if properly maintained.
- Durability class (in ground): Slightly lower, but still impressive.
- Resistance: Excellent against rot, termites, and marine borers.
That said, the sapwood (lighter outer layer) is prone to powder-post beetle attack, so it’s best to use heartwood or ensure sapwood sections are treated before installation.
🔨 Workability: A Tough Wood That Rewards Effort
If working with Merbau you must be patient and use sharp tools. Its density makes it a bit challenging to cut and nail — but the payoff is stunning.
- Sawing and planing: Moderately easy when green, slightly harder when dried.
- Nailing and screwing: Always pre-drill holes to avoid splitting.
- Finishing: Polishes well, finishes very evenly and takes stain or paint consistently.
- Maintenance: Since it is high in natural oils, there is little treatment needed other than occasional oiling for nurturing its appearance and durability.
It’s not at all beginner-friendly like softer woods such as pine, but pros and DIYers alike say the extra trouble is worth it.
🏡 Common Uses of Merbau Wood
Merbau is one of the most versatile hardwoods available today. Here’s where you’ll often find it used:
Outdoor Applications
- Decking: Strong and weather resistant, it’s a favorite for luxury decks.
- Pergolas and patios: Retains beauty in heat, cold, sun and rain.
- Outdoor furniture: Tables, benches and lounges can be perfect for the great outdoors that last a lifetime.
- Boardwalks and bridges: Its durability makes it appropriate for heavy public or marine construction.
Indoor Applications
- Flooring: Adds warmth and elegance to interiors; resistant to dents and wear.
- Staircases and balustrades: Its depth and texture are an ideal complement to today’s modern and even traditional homes.
- Cabinetry and furniture: Merbau’s fine finish gives a luxurious touch to any room.
- Musical instruments: Valued for tonal quality and stability.
💎 Advantages of Merbau Wood
Let’s talk about why Merbau continues to be one of the world’s most loved hardwoods:
1. Exceptional Durability
With its natural oils and dense structure, Merbau is built to last — even in outdoor settings where many timbers fail.
2. Beautiful Appearance
The deep reddish-brown color, interlocked grain, and subtle sheen make Merbau a visual standout. It adds richness and warmth to any space, indoors or out.
3. Excellent Dimensional Stability
Unlike some timbers that expand or contract wildly with moisture, Merbau holds its shape — a key advantage for flooring and decking.
4. Termite and Decay Resistance
Few hardwoods can resist pests and decay as naturally as Merbau. Its heartwood is practically immune to termites.
5. Long Service Life
When properly installed and maintained, Merbau structures can last 40–60 years or more.
⚠️ Disadvantages of Merbau Wood
No wood is perfect — and Merbau, even with all its virtues, has a few downsides to consider.
1. Tannin Bleeding
Merbau is rich in tannins, which can leach out when first exposed to moisture, staining nearby concrete, tiles, or walls. This problem can be avoided by rinsing and sealing the product prior to installation.
2. Heavier and Harder to Work With
It’s also very dense and not easy to cut or nail without the right tools. Pre-drill to help avoid splitting.
3. Color Fading Over Time
If left untreated Merbau will slowly fades to a silver grey colour over time. Oil it at regular intervals to maintain its rich color.
4. Higher Cost
It’s also not the cheapest — but its long lifespan often justifies the investment.
5. Ethical Sourcing Concerns
Merbau is grown in tropical regions, so you should avoid adding to illegal logging by purchasing from certified sustainable suppliers.
💡 Tips for Using Merbau in Your Projects
If you’re planning to use Merbau, keep these practical tips in mind:
- Pre-drill before fastening — reduces the risk of splitting and improves tight hold.
- Allow for drainage — especially for decking, to minimize moisture retention.
- Rinse new boards — take out tannins prior to sealing or oiling.
- Regular maintenance — apply oil or sealant every 6–12 months to retain color and sheen.
- Choose certified timber — look for FSC or PEFC certification to ensure ethical sourcing.
🌦️ Merbau vs Other Hardwoods
| Property | Merbau | Ironbark | Teak | Spotted Gum |
| Density | 850–860 kg/m³ | 1,100 kg/m³ | 650 kg/m³ | 950 kg/m³ |
| Durability (above ground) | Class 1 | Class 1 | Class 1 | Class 1 |
| Maintenance | Low | Medium | Low | Medium |
| Cost | Moderate-High | High | Very High | Moderate |
| Ideal Use | Decks, floors, furniture | Heavy outdoor | Marine, luxury furniture | Decking, flooring |
Merbau strikes a great balance between strength, looks, and cost, making it a practical and premium option for most applications.
🌍 Sustainability and Environmental Impact
Because Merbau originates mainly from tropical forests, responsible sourcing is critical. Deforestation and illegal logging have historically been concerns with this species.
Before buying, always check for:
- FSC (Forest Stewardship Council) or PEFC certification.
- Suppliers who source from legal and sustainable forests.
Many Australian and international distributors now offer ethically harvested Merbau, ensuring you can enjoy its beauty without harming the planet.
🔧 Maintenance and Care
To keep your Merbau deck or floor looking great for decades:
- Clean regularly with mild soap and water.
- Avoid harsh chemicals that can strip natural oils.
- Continue the re-oiling process every 6–12 months so that it retains its rich colour.
- Use a UV-resistant oil to keep it from fading.
With very little maintenance, Merbau will maintain its looks and performance for years to come.
🧠 Final Thoughts
Merbau has the perfect mix of power, attractiveness, and long-term viability to be called an ideal material. No matter if you are building a rich outdoor deck, the most suitable bedroom flooring, or a stunning furniture item, this wood will give you both the beauty and the functionality.
It is true that it takes slightly more work to handle and that the money has to be spent first — but the outcome is a material that will keep its appeal for as long as your taste is.
So, if you are a fan of strength and still want your home to be filled with the timeless character of a natural material, then Merbau wood is definitely a high-end choice.
❓ FAQs About Merbau Wood
1. Is Merbau good for outdoor use?
Absolutely. With a high-density structure and natural oils, it’s wonderfully tough – classified Class 1 for durability so is the perfect option for decking, pergolas and outdoor furniture.
2. How long does Merbau decking last?
With proper maintenance, Merbau decks can last 40–60 years or more.
3. Does Merbau need sealing?
Yes — sealing or oiling can prevent color fading and tannin leaching, particularly in the first few months after your deck has been installed.
4. Is Merbau termite resistant?
The heartwood offers natural resistance to termites and decay, but untreated sapwood is non resistant and it should be treated or avoided.
5. Is Merbau environmentally friendly?
It can be, if sourced responsibly. Always buy FSC-certified or sustainably harvested Merbau to ensure it comes from legal, managed forests.
✨ In a Nutshell
Merbau is more than just a hardwood; it symbolizes power, opulence, and timeless handcrafted art. Whether you are making a backyard oasis or upgrading your home’s interior, this amazing wood is a perfect blend of class and high quality.
