Overview

Spotted gum is a premium native Australian hardwood prized for its strength, natural durability and distinctive character. The common name covers several closely related Corymbia species that grow along the east coast of Australia. Timber is widely available and used across structural, exterior and interior applications. The trees shed smooth bark in irregular patches, creating the characteristic “spotted” trunk that gives the species its name.

Appearance

• Heartwood: Light brown through to rich red‑brown; sapwood is pale straw to light brown.
• Grain and figure: Back‑sawn boards often show lively figure; wavy grain can produce attractive fiddle‑back effects.
• Texture: Even to slightly coarse; occasional gum veins and natural features may be visible.
• Feel: The wood can feel slightly greasy, which contributes to clean machining.

Workability

• Machining/boring: Cuts cleanly; the high density benefits from sharp tooling and steady feed rates.
• Fixing: Pre‑drilling is recommended for nailing and screwing to reduce splitting.
• Gluing: Reliable bonds with appropriate surface preparation; wipe oily surfaces before gluing.
• Finishing: Takes oils, stains and clear finishes well; also suitable for carving and woodturning.
• Staining/bleed: Typically lower tannin bleed‑through than many eucalypts, aiding finishing consistency.

Performance & durability

• Natural durability: High – commonly specified for exposed and structural applications when detailed and maintained correctly.
• Bushfire use: Components 18 mm and thicker can be used in bushfire‑prone construction without fire‑retardant treatment (per WoodSolutions guidance).
• Decay/biological resistance: Excellent general performance; for in‑ground or marine exposure, follow the relevant standards and treatments.
• Movement/stability: Moderate movement when properly seasoned and installed with good detailing.
• Durability class: Class 1 (above‑ground); Class 2 (in‑ground) – per WoodSolutions.
• Termites: Generally not resistant; adopt termite management appropriate to the site.
• Lyctid borer: Sapwood is susceptible; treat or exclude sapwood where required.

Structural/grades

• Extensively used in engineering works: wharves, bridges, railway sleepers, cross‑arms and mining timbers.
• In building, selected for posts, poles, structural framing and trusses where high strength is required.
• Available in appearance grades for flooring, lining, decking and cladding.

Typical applications

• Flooring, stairs, benchtops and interior joinery.
• Decking, cladding and external joinery (with correct detailing and finishing).
• Structural framing, posts/poles, bridge and wharf construction, sleepers and cross‑arms.
• Veneer and plywood manufacture.
• Boatbuilding, tool and implement handles, carving/woodturning, sporting goods (e.g. polo sticks), and diving boards.

Key properties (indicative)

• Density at 12% MC (seasoned): ~950 kg/m³
• Density (green/unseasoned): ~1200 kg/m³
• Modulus of Rupture (MOR): ~140 MPa (seasoned)
• Modulus of Elasticity (MOE): ~22.0 GPa (seasoned)
• Janka hardness: ~11.0 kN
• Shrinkage (green to 12% MC): Tangential ~7.1%; Radial ~4.3%

Note: Values are indicative for the spotted gum species group and can vary with resource and processing. Refer to the WoodSolutions profile for detailed property tables and design data.

Source & attribution

Content on this page is original wording prepared for this site, based on publicly available technical information.

• Primary reference: WoodSolutions — Gum, Spotted