Few hardwoods combine workability, weather resistance and visual warmth quite like Merbau. This tropical timber from the forests of Southeast Asia has been a favourite among cabinetmakers, architects and garden designers for decades — and for good reason. Dense enough to resist rot and insects, yet forgiving enough to machine to a smooth finish, Merbau earns its reputation as a true all-rounder. On this page you will find everything you need to know: where it comes from, what makes it special and how to keep it looking its best year after year.
Looking for solid hardwood outdoor furniture that shares Merbau's spirit of durability and warmth? Browse our garden furniture collection — built from comparable tropical hardwoods and designed to last a generation.
Merbau's scientific names — Intsia bijuga and Intsia palembanica — give away its family roots in the legume order. The trees grow across a broad arc stretching from Myanmar and Malaysia through Indonesia to the Pacific islands, favouring coastal lowlands and riverine forests. In the right conditions they reach 45 metres in height, with a clear, branch-free trunk of 15 to 25 metres — ideal for producing long, stable boards.
What makes Merbau commercially interesting is also what makes it ecologically sensitive: the trees grow at very low density, averaging roughly one harvestable specimen per two hectares. That scarcity, combined with global demand, is why responsible sourcing matters so much when choosing Merbau products.
The heartwood — the part used in furniture and flooring — is distinctly different from the pale sapwood. It develops its characteristic colour and extractive compounds only as the tree matures, which is why full-grown specimens produce the most prized timber.
Merbau sits firmly in the premium hardwood category — dense, stable and naturally resistant to outdoor exposure. Here is how its main characteristics measure up:
| Property | Detail |
|---|---|
| Colour (heartwood) | Yellow-brown to rich reddish-brown; deepens to dark red over time |
| Grain | Interlocked or wavy; produces a striking ribbon figure when quarter-sawn |
| Texture | Medium to coarse; uniform and consistent |
| Density | 700 – 900 kg/m³ (air-dry) |
| Durability class | Class I – II (very durable to durable) for heartwood |
| Natural resistance | High resistance to rot, fungi and most wood-boring insects |
| Shrinkage | Low; relatively stable once properly dried |
| Workability | Good to very good; responds well to machine and hand tools |
The combination of high density, natural oil content and durability class I–II makes Merbau suitable for a wide range of applications, from exposed exterior projects to fine interior joinery.
Prefer a ready-made solution built to the same hardwood principles? The products below are designed for Finnish outdoor conditions — stable, weather-resistant and low-maintenance.
Merbau is considered a good-natured timber to work with, but a handful of its natural characteristics require attention in the workshop.
The interlocked grain can cause tear-out if you cut with the grain running the wrong way. A skew angle of around 20° on planer blades significantly reduces this risk. Carbide-tipped tools are preferred — the dense, silica-rich fibres blunt high-speed steel faster than softer species.
At densities of up to 900 kg/m³, Merbau will split under direct nailing or screwing. Pre-drilling pilot holes is not optional — it is essential. Use stainless-steel fasteners for exterior work; the tannins in Merbau react with standard steel and iron, causing black staining that is very difficult to remove.
One of Merbau's most discussed characteristics is its tendency to bleed. The heartwood contains water-soluble yellow and red extractives (primarily flavonoids) that leach out when the wood gets wet. On decking this produces reddish-brown run-off that can stain adjacent paving or walls. Practical steps to manage it:
The natural oil content can interfere with adhesive bonding. Wipe gluing surfaces with a clean, dry cloth immediately before applying adhesive, and use a hardwood-compatible adhesive (polyurethane or resorcinol-based). Oil finishes and UV-stable hardwood oils are the most practical surface treatments — they feed the wood and are easy to reapply.
Merbau's durability class means it can survive outdoors with minimal intervention — but "low maintenance" is not the same as "no maintenance". A simple annual routine keeps the wood stable, prevents surface checking and preserves its colour.
Merbau's combination of low natural density in the forest and high commercial demand has placed it under significant harvesting pressure in several parts of its range — particularly in Papua New Guinea and Indonesia. That pressure has resulted in Merbau being listed on the IUCN Red List as vulnerable in some regions.
Two certification schemes are widely used to signal responsible forest management in the timber trade:
When buying Merbau, asking your supplier for documentation of legal harvest origin and, where available, third-party certification is a straightforward step that supports better forestry practices. Well-managed Merbau from certified sources can be a long-lasting, low-waste choice — one piece of quality hardwood furniture or decking replacing many cycles of cheaper, shorter-lived alternatives.
Yes. Merbau's durability class I–II means the heartwood resists rot and fungal attack well in temperate and cold climates. Its natural density also makes it less prone to frost-related cracking than softer, more porous species. The key in Finnish conditions is to ensure good drainage under decking, use stainless-steel fixings and apply a penetrating hardwood oil at the start of each season.
Both are tropical hardwoods in durability class I–II, and both contain natural oils that contribute to outdoor performance. Teak tends to have a slightly higher silica content, which can blunt tools faster. Merbau is often more affordable and produces a warmer, redder tone. Teak is generally considered more dimensionally stable over wide boards. For most garden furniture and decking applications, both perform excellently with proper maintenance.
Merbau heartwood contains soluble flavonoid extractives that leach out in contact with water — this is the "bleeding" effect. The run-off is reddish-brown and can stain concrete, stone or composite surfaces. The effect is most pronounced in new timber and diminishes over time. Pre-washing new boards, using kiln-dried timber and prompt oiling all reduce the amount of leaching. Any fresh staining on paving can usually be rinsed off before it dries.
Film-forming finishes such as paint or varnish are not ideal for Merbau outdoors. The wood's natural movement and oil content cause film finishes to peel or crack over time. A penetrating hardwood oil is far more practical: it feeds the wood, is easy to reapply and does not flake. For interior furniture a hard-wax oil or a two-component lacquer can work well on properly de-greased surfaces.
Both species are sold commercially as "Merbau" and are essentially interchangeable for most practical purposes. Intsia bijuga has a broader natural range (extending into the Pacific islands), while Intsia palembanica is more concentrated in the Malay Peninsula and Sumatra. Timber properties — density, colour, durability — are very similar between the two species.
Merbau sets a high benchmark — and the garden furniture and accessories in our collection are built to the same principles: dense, durable hardwoods and weather-resistant materials designed for years of outdoor use. Whether you are furnishing a terrace, protecting your existing furniture over winter or looking for a piece the whole family can enjoy, there is something here for every garden.
Explore the full range in our garden furniture collection — and discover how the right hardwood choice pays for itself over a generation.
