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The name balau is also used for some species of Hopea.
- Medium to large hardwoods.
- Often buttressed.
- Straight cylindrical bole 30–50m long.
Shorea spp. grow across:
- Heartwood is red-brown to purple-brown.
- Sapwood is distinctly paler.
- Grain varies from straight to interlocked.
- Interlocking grain produces striped figure (pattern) on quarter-sawn timber.
- Texture moderately coarse but even.
- Engineering: heavy engineering.
- Construction: framing, flooring, linings, joinery, fencing.
- Decorative: turnery.
- Others: boat building, vats, casks.
- Density: 840kg/m3 at 12% moisture content; about 1.2m3 of seasoned, sawn timber per tonne.
- Strength groups: S3 unseasoned, SD4 seasoned.
- Stress grades: F8, F11, F14, F17 (unseasoned); F11, F14, F17, F22 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes.
- Joint groups: JD2 seasoned.
- Shrinkage to 12% MC: shrinkage rates vary considerably between species.
- Unit shrinkage: not available.
- Durability above-ground: Class 4 (life expectancy less than 7 years).
- Durability in-ground: Class 4 (life expectancy less than 5 years).
- Lyctine susceptibility: untreated sapwood is susceptible to lyctine borer attack.
- Termite resistance: not resistant.
- Preservation: sapwood readily accepts preservative impregnation.
- Seasoning: be careful when drying to avoid splits, checks and distortion.
- Hardness: hard (rated 2 on a 6-class scale) to indent and work with hand tools.
- Machining: resinous material gums up cutting edges, otherwise relatively easy to machine and turn.
- Fixing: pre-bore when nailing.
- Gluing: as with most high-density species, machine and prepare surface immediately before gluing.
- Finishing: satisfactory to paint, stain and polish.
- Sapwood: well defined and paler than heartwood.
- Heartwood: purple-red or dark red-brown.
- Texture: moderately coarse, even, interlocked grain; hard to cut across end grain; end cut is generally shiny with a degree of lustre on a dressed surface.
- Vessels: mostly solitary with a few radial or oblique groups, medium size, even and diffuse distribution; tyloses are numerous; vessel lines present.
- Parenchyma (soft tissue): apotracheal—consists mainly of irregular spaced bands and occasional short tangential lines or diffuse strands; paratracheal—often as incomplete vasicentric strands around the vessels, barely visible by hand lens, scant to well-defined aliform.
- Rays: fine, generally inconspicuous on the radial surface.
- Burning splinter test: match-size splinter burns to a charcoal.
- Intercellular canals: generally filled with white resin, smaller than the vessels, and arranged in concentric formation.
Research and resources
- Ilic, J 1991, CSIRO atlas of hardwoods, Crawford House Press, Bathurst, Australia.
- Queensland Government, DAF 2018, Construction timbers in Queensland: Properties and specifications for satisfactory performance of construction timbers in Queensland. Class 1 and Class 10 buildings, Books 1 & 2, Department of Agriculture and Fisheries, Brisbane.
- Standards Australia, 2000, AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes, Standards Australia International, Strathfield, NSW.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018