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Merbau

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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.

Appearance

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

Workability

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

Readily Available

NSW

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.

Availability - Further Information

Native Forest

Shrinkage

Very Low Low Medium High Very High

Tangential :

2.50%

Radial:

1.20%

Unit Movement Tangential:

0.30%

Unit Movement Radial:

0.19%

Strength Group

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

Seasoned:

SD1

SD2

SD3

SD4

SD5

SD6

SD7

SD8

Stress Grade

Structural
No. 1
Structural
No. 2
Structural
No. 3
Structural
No. 4
Structural
No. 5

Unseasoned:

F27

F17

F14

F11

F8

Seasoned:

F27

F22

F17

F14

F11

Density per Standard

Seasoned:

860kg/m3

Unseasoned:

1150kg/m3

Joint Group

Very High

High

Reasonably High

Medium

Low

Very Low

Unseasoned:

J1

J2

J3

J4

J5

J6

Seasoned:

JD1

JD2

JD3

JD4

JD5

JD6

Colour

  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:

118

Modulus of Rupture - Seasoned:

147

Modulus of Elasticity - Unseasoned:

15

Modulus of Elasticity - Seasoned:

18

Maximum Crushing Strength - Unseasoned:

59

Maximum Crushing Strength - Seasoned:

82

Impact - Unseasoned:

18

Impact - Seasoned:

7.7-14

Toughness - Unseasoned:

Medium - 15 - 24 Nm

Toughness - Seasoned:

Medium - 15 - 24 Nm

Hardness - Unseasoned:

7.6

Hardness - Seasoned:

8.5

Durability

Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)

In-Ground:

(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

Lyctid Borer Susceptibility - Other:

Termite Resistance:

Resistant

Fire Properties

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
Number:

Average Specific Extinction Area:

<250

Bushfire Resistance:

BAL 12.5, 19 and 29 – All AS3959 required applications

Joinery

Timber joinery products offer a classic, unique and stylish touch to any interior or exterior design. The products are produced for a variety of internal applications including door and window frames, cabinetry, skirtings, mouldings and architraves. When looking to the outdoors, joinery products range from decorative eaves and posts to eye-catching railings.

Many timber species are suitable for joinery products and care should be taken in selecting the perfect timber for the particular product and its intended finish. Rare and exotic species such as Teak and Rosewood can generate pieces of outstanding beauty but material cost and availability are also important considerations.

Commercially available species like Tasmanian oak, Australian cypress, spotted gum and the like, often make the more practical choice, with the added benefit that they can be easily matched with other timber products within the building, like flooring.

Solid timber for joinery products is generally supplied as ‘clear finish grade' but ‘paint grade' options are available and these are usually comprised of a composite material like MDF or glulam.

A large number of specialist suppliers and producers offer the consumer extensive choice of profiles for all of the most common and popular joinery products. Choice is in many cases, limited only by imagination.

Cabinetry is often associated with joinery and most typically includes, cupboards, benches and other similar ‘built in' furniture. Like joinery, cabinetry is generally specified as either paint or clear finish grade and naturally for clear finish grade timbers, appearance and surface finish are critical in achieving a successful application.

 

Decking

Download the WoodSolutions Technical Design Guide on Domestic Timber Decking here.

Timber decks are a practical and attractive addition to any outdoor landscape. Natural timber decks blend seamlessly with their surrounding environment and will serve as popular entertaining areas all year long.

As an external structure, carrying large loads of traffic, timber decking has high structural performance requirements. In addition decks are usually raised clear off the ground and fully exposed to the weather meaning an effective deck must be able to cope with wear and tear from repeated use and in addition discharge rainwater efficiently. Roundin the corners (easing the arris) of the decking will help run off water while spacing for ventilation between the decking boards will prevent water ponding on the deck surface. 

Timber decking is available in both seasoned and unseasoned wood, in a wide range of species, sizes and grades. The natural appeal and strength of timber makes it a practical choice for outdoor decking. This guide provides an overview of best practice methods for specifying, installing and finishing a timber deck.

Stairs, Exterior

All exterior stairs serve a functional purpose, but the choice of timber in the application will turn a functional building element into an aesthetically pleasing feature. And while the construction of stairs is demanding, the investment of time will be returned, with a well constructed timber staircase typically lasting decades.

Exterior stairs are usually built from treated softwood and durable hardwoods and typically finished with paint. The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.

When it comes to stairs there is a multitude of variations available for application depending on the structural requirements of the building. This guide discusses the most commonly specified stair types.

Rails and Balustrades, Interior

The versatility, beauty and strength of timber makes it the ideal material choice for interior handrails and balustrades. Treated softwood and durable hardwoods are the most popular timber choices and these can be turned to create a range of unique styles and designs to suit a variety of tastes and decors.

When used internally balustrades and handrails are typically finished with a clear lacquer to showcase the natural beauty of the timber and with appropriate care and attention will last a lifetime. Find here general information on member sizes, connections and suitable materials, as well as important considerations, for the specification and construction of interior handrails and balustrades.

Stairs, Interior

Interior staircase work is considered a specialised area of carpentry and joinery as its construction requires high levels of workmanship, detail and accuracy. Many interior stairs are built from quality joinery timber, cut and seasoned especially for staircases. Interior stairs differ considerably in design, from simple straight flights, commonly used in domestic work, to more elaborate stairs, constructed purposely as stand out features in public and commercial buildings.

The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.

Pergolas

Timber pergolas offer an attractive and economical way to create functional living and entertainment areas in the outdoors.  Pergolas designed with care can maximise both winter sunshine and summer shade, ensuring outdoor living is enjoyed all year round. With its natural look, durability and versatility there are few other materials that can match the advantages of timber in pergola construction.

Pergolas are typically constructed via a straightforward post and beam process, which can be attached to an existing building or form a free standing structure. A protective finishing coat will preserve the life of the pergola and a variety of paints and stains are available on the market to facilitate this.

 

Rails and Balustrades, Exterior

The versatility, strength and natural beauty of timber makes it the ideal material choice for external handrails and balustrades. Usually built from treated softwood and durable hardwoods these timbers can be turned to create a range of styles and designs, resulting in balusters that are unique as they are individual. Painting, staining and oil based finishes broadly cover the wide range of finishing options available and with the appropriate care and attention a timber balustrade can last a lifetime.

This guide provides general information on member sizes, connections and suitable materials to enable the construction of a long lasting, attractive and durable timber handrail or balustrade.

Windows

Timber windows are usually supplied as joinery items with a primer or base coat, as factory glazed components requiring site finishing or as fully glazed and finished windows.

Demand is ever increasing for high performance windows that promote efficient energy use in buildings. Careful window selection and placement is rightly viewed as a means of reducing demand for artificial light and climate control. Timber is an ideal material when considering these aspects as it is a material that is light, strong, natural and renewable. It can be moulded to any shape, so will meet the thermal, acoustic and design requirements of even the most unusual window.

This guide discusses the common elements involved in specifying, constructing and installing timber windows

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.

Timber flooring is a timeless product, offering a warmth and natural beauty largely unmatched by other flooring options. This article provides an overview of the installation of solid timber strip flooring over bearers and joists, timber based sheet flooring products and concrete slabs. Timber flooring is typically supplied as either solid timber or laminated wood products, made from layers of bonded timber. It fits together with a tongue and groove joint and once in place, is sanded and finished. There is a wide variety of species to select flooring from and the right species for a given application will be dependent on numerous factors. Information relating to species selection, environmental assessment, finish selection and recommended maintenance routines are all provided in this section.

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