Merbau | Insia Bijuga

Merbau is a popular hardwood from South East Asia used in a wide range of applications; from construction to indoor and outdoor furniture.

Other Names: Kwila, Ipil, Vesi, Johnstone River Teak or Scrub Mahogany


Merbau is a popular hardwood derived largely from areas in South East Asia, Papua New Guinea, the Pacific islands, and northern Queensland. With its high degree of natural durability and strength it is used externally in engineering, construction and marine applications. Merbau also features in backyards as outdoor furniture, and internally in a range of joinery, flooring and other uses.

Merbau is harvested from tropical forests and, in some cases, may be sourced from forests legally converted to other land uses or where there are inadequate controls. Certified merbau is available in Australia, so it is suggested you check with your supplier. Certification and chain of custody systems, including DNA tracking, will provide assurance that the wood is from legal and/or well managed forests.

In its natural setting in North Queensland, Malaysia, Fiji, Vietnam, the Philippines, Madagascar, Papua New Guinea, Thailand, Solomon Islands, New Caledonia, Vanuatu and Samoa, the merbau species can grow up to 40 metres in height, with a 0.6 metre trunk diameter. The bushy tree, with distinctive local names, will often form a spreading canopy.

The attractive yellow-orange brown hue of freshly cut heartwood deepens or reddens with ageing. This contrasts markedly with the merbau sapwood, which is white, pale yellow or buff coloured. If left untreated, the sapwood is susceptible to lyctid borer attack. Beyond that, merbau is quite resistant to termites and seasons well with kiln or air-drying, exhibiting only a low degrade and very little shrinkage or movement. The grain of merbau can vary but it is usually interlocked or wavy, with a coarse but even texture, often prized for its attractiveness on backsawn material.

It will finish well with paint, stain, and polish although gum bleed is a possibility.   Merbau is a versatile wood product. It is utilised for larger-scale projects and general construction, along with common use for outdoor settings and barbeque trolleys, and for joinery, flooring and fitting purposes. As it turns well and responds to hand tools it can be applied to more specialised work, such as cabinet making, musical instruments, boat building, carving and tool handles.



Very Low Low Medium High Very High
Radial: 0 - 2

Strength Group

Very High High Reasonably High Medium High Medium Reasonably Low Low Very Low

Stress Grade

No. 1
No. 2
No. 3
No. 4
No. 5
Unseasoned: F27 F17 F14 F11 F8
Seasoned: F27 F22 F17 F14 F11

Density per Standard

Unseasoned: 1150 kg/m3
Seasoned: 850 kg/m3

Joint Group

Very High High Reasonably High Medium Low Very Low


  White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky

Mechanical Properties

Modulus of Rupture - Unseasoned: 103
Modulus of Rupture - Seasoned: 130-147
Modulus of Elasticity - Unseasoned: 15-18
Modulus of Elasticity - Seasoned: 12-18
Maximum Crushing Strength - Unseasoned: 55
Maximum Crushing Strength - Seasoned: 63-81
Impact - Unseasoned: 18
Impact - Seasoned: 7.7-14
Toughness - Unseasoned: Medium - 15 - 25 Nm
Toughness - Seasoned: Medium - 15 - 25 Nm
Hardness - Unseasoned: 7.6
Hardness - Seasoned: 7.2-8.6


Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)
(0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)
Above ground:
(0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)
Marine Borer Resistance:
Lyctid Borer Susceptibility: Susceptible
Termite Resistance: Resistant

Fire Properties

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
EFH Ignitibility:
0 1 2 3 4 5 6 7 8 9 10
EFH Spread-of-Flame Index:
EFH Smoke-Developed Index:
1 - non-combustible 2 - reasonably non-combustible 3 - slightly combustible 4 - combustible
Fire Properties Group
Average Specific Extinction Area: <250
Bushfire Resistance: BAL 12.5, 19 and 29 – All AS3959 required applications


Botanical Name: Insia Bijuga
Preferred Common Name: Merbau
Other Names: Kwila, Ipil, Vesi, Johnstone River Teak or Scrub Mahogany
Species Type: Hardwood


In its natural setting the merbau species can grow up to 40 metres in height, with a trunk of 0.6 metres in diameter. The bushy tree will often form a spreading canopy. Once cut, the heartwood will initially appear as yellowish-brown or orange-brown before deepening to a pale to dark reddish brown. This contrasts with the merbau sapwood, which appears white, pale yellow or buff. The wood grain is variable but usually interlocked or wavy, which produces a ribbon figure on the radial surface. The timber has a coarse but even texture. It has a characteristic oily odour when cut.

Common Applications

Merbau spans a variety of uses in the fields of engineering, construction, marine and furnishings, both for the indoors and outside. It has been utilised for infrastructure projects including cross arms, bridge building, piles, sleepers, posts, wharves and mining timbers. In the construction context merbau is used in framing, decking, treads and other general needs. Many boats, particularly the decks, are made of merbau, as are a variety of vats, musical instruments and tool handles. As a furniture material merbau is prominent in outdoor settings and barbeque trolleys, as well as being valued for turning, paneling, joinery, shop fitting, cabinet making, parquet flooring, carving, veneer, counter and bench tops.

Common Form

Sawn, Veneer


Merbau takes well to paint, stain and polish, however the finish can sometimes be affected by gum bleed-through or oily patches. Its vessels also contain a yellow substance that stains textiles and concrete. It turns well and is relatively easy to work with hand tools, though it can be variable when it comes to machining. It will generally cut cleanly but there may be some blunting or gumming effect on the cutting edges. Merbau tends to split unless pre-bored, but holds fastenings well.

Origin of Timber

QLD, Asia, SE Asia, Oceania

Readily Available

NSW, VIC, SA, TAS, QLD, WA, NT, NZ, Asia, SE Asia, Oceania

Availability - Further Information

Merbau grows naturally in South East Asia, the Philippines, Solomon Islands, Fiji and Papua New Guinea and is imported to Australia from these countries. Merbau grows in Australia in a specific region by the Johnstone River and in the Daintree area of Far North Queensland. It is often referred to as Johnstone River teak or scrub mahogany.

Source of Timber

Native Forest, Plantation


  • Decking

    Timber decking creates spaces that are functional, practical and aesthetically pleasing. With the right design and care a timber deck will make a valuable addition to any home or business, creating an outdoor living space that will be enjoyed for years to come.

  • Exterior Rails and Balustrades

    This guide provides general information on member sizes, connections and suitable materials for construction of handrails and balustrades in external applications. Commonly built from treated softwood and durable hardwoods, they can be finished with a wide variety of paints or stains, creating balustrades that with the right care and attention, will comfortably withstand the elements for decades to come.

  • Exterior Stairs

    For outdoor applications, timber is one of the leading material choices. Timber use in external staircase applications creates structures of strength and durability, sheathed in a natural beauty that blends seamlessly with the outdoor environment.

  • Flooring

    Whether for structural or finished flooring applications, timber offers durability, versatility and adaptability. The warmth, strength and natural beauty of timber flooring has proved enduringly popular in a wide variety of interior settings.

  • Interior Rails and Balustrades

    With its natural beauty and inherent strength, timber is a popular material choice in internal balustrade construction. Commonly built from treated softwoods and durable hardwoods, interior balustrades and handrails are typically finished with a clear lacquer to generate the most natural result.

  • Interior Stairs

    Timber should be the material of choice for designers seeking internal staircases of strength, beauty and durability. The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.

  • Pergolas

    A timber pergola is a practical, functional and attractive way to extend living and entertainment spaces into the outdoors.

  • Timber Joinery Products

    Timber joinery products offer a classic, unique and stylish touch to any interior design.

  • Timber Portal Frames

    For buildings that require large spans and column free interiors, timber portal frames provide one of the most aesthetically pleasing solutions. Utilising modern engineering technology, portal frame design transforms timber into a highly effective, efficient and economical structural product. This application guide provides a comprehensive overview of the process of using timber in the specification, fabrication and erection of portal frame structures.

  • Windows

    With natural aesthetic appeal, versatility and sound structural performance, timber provides excellent window joinery design options. Whether stained to bring out natural tones, or painted to compliment particular décors, timber windows can be tailored to suit a huge variety of styles and can be installed into any type of building.

Case Studies

All Comments (1)

Sign In or Sign Up now to post a comment! $session.setAttribute("REDIRECT_AFTER_LOGIN","$URLMapContent.URL_MAP_FOR_CONTENT")