Balau
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Other Names
Selangan Batu, Gisok, Belangeran, Empenit Thitya, Teng, Alan, Shorea glauca, Maxwelliana, Shorea seminis, Shorea laevis
Native to Malaysia, Indonesia and the Philippines, balau is a dense hardwood used mainly for heavy construction.
Native to Malaysia, Indonesia and the Philippines, balau is a dense hardwood used mainly for heavy construction.
The heartwood of balau is yellow to brown, which is distinct from the paler sapwood. Its moderately fine and even texture presents an interlocked grain, which produces a stripe figure on the radial surface. Balau is also susceptible to pinhole borer damage.
In relation to its density, balau is relatively easy to work. It does not contain silica, however resin pockets may be present, meaning resin can build up on cutting equipment. Pre-drilling is advisable when nailing. Balau can be painted, stained and polished but is not suitable for steam bending
Balau is not often seen in Australia. Not to be confused with the more common red and yellow balau timbers, balau (Shorea albida) is used for heavy construction, wharfage, sleepers and shipbuilding.
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Botanical Name
Shorea albida
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Preferred Common Name
Balau
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Species Type
Appearance
Balau features heartwood that is of a yellow to brown colour and has a paler sapwood, which can be up to 50 mm wide. Its moderately fine and even texture presents an interlocked grain, which produces a stripe figure on the radial surface. Resin pockets may also be present. Balau is susceptible to pinhole borer damage.
Common Applications
Of high strength and durability, balau is mainly used for heavy construction. It is also used for wharfage, sleepers, ship building.
Common Form
Sawn
Workability
Although balau is a high-density hardwood, it is relatively easy to work. The main workability issue is due to the presence of resin pockets, which means resin can build up on cutting equipment. If balau is being nailed, the timber should be pre-drilled. Any machining and surface preparation should be done immediately before gluing. Balau is not suitable for steam bending.
Origin of Timber
Availability - Further Information
Availability - Further Information
Shrinkage
| Very Low | Low | Medium | High | Very High | |
Tangential : |
7.30% |
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Radial: |
4.50% |
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Unit Movement Tangential: |
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Unit Movement Radial: |
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: |
900kg/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: |
103 |
|---|---|
Modulus of Rupture - Seasoned: |
|
Modulus of Elasticity - Unseasoned: |
18.3 |
Modulus of Elasticity - Seasoned: |
|
Maximum Crushing Strength - Unseasoned: |
66 |
Maximum Crushing Strength - Seasoned: |
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Impact - Unseasoned: |
|
Impact - Seasoned: |
|
Toughness - Unseasoned: |
High - 25 Nm and above |
Toughness - Seasoned: |
|
Hardness - Unseasoned: |
9.5 |
Hardness - Seasoned: |
Durability
| Low | Moderate | Reasonably High | High | |
| (0 - 5 yrs) | (5 - 15 yrs) | (15 - 25 yrs) | (more than 25 yrs) | |
In-Ground: |
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| (0 - 7 yrs) | (7 - 15 yrs) | (15 - 40 yrs) | (More than 40 yrs) | |
Above ground: |
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| (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: |
Not Resistant |
Fire Properties
| 1 - non-combustible | 2 - reasonably non-combustible | 3 - slightly combustible | 4 - combustible | |
Fire Properties Group |
Group Number - Other: |
3 if used on MDF or particleboard ≥12mm; veneer thickness 0.6-0.85mm |
|---|---|
Average Specific Extinction Area: |
<250 |
Bushfire Resistance: |
BAL 12.5 and 19 – All AS3959 required applications |
Retaining Walls (Landscaping)
The natural appeal, strength and versatility of timber makes it an ideal choice for retaining wall landscaping applications.
Retaining wall systems include cantilevered round or sawn timber, mass wall and crib wall construction. Walls up to one metre in height follow a basic design and can usually be constructed using standard proprietary wall systems. An engineer will be required to plan and design walls greater than one metre, including the footings and drainage.
Drainage of retaining walls is a critical factor in influencing the long term stability of the wall and should thus form a significant part of the design and planning process.
Regular care and maintenance of retaining walls is essential in ensuring the long-term stability and safety of the structure.
Structural Timber Poles
Timber pole construction is typically utilised to provide support for gravity loads and resistance against lateral forces. The natural appeal of timber ensures that its role is not purely structural however, with timber poles complimenting architectural designs aimed at harmonisation with the natural environment. The small number of footings required in pole frame construction also ensures minimal disturbances to the site.
With a double bearer system, poles can be spaced further apart than is usual, creating a more spacious building interior, that allows greater interior design flexibility. While poles are usually placed in a grid like system this is not compulsory and the flexibility of the application means the system can cope with a wide variety of designs, enabling designers to take full advantage of beautiful outlooks.
This article provides a comprehensive overview of the process involved in specifying, designing and constructing a solid timber pole construction.
