Appearance of Grey Ironbark Timber
The timber of Grey Ironbark is distinctively beautiful, with heartwood ranging from light grey or chocolate brown to darker reddish hues, sometimes accented by black streaks. The sapwood contrasts sharply, being almost white and typically around 20mm thick. The grain is generally tight and straight, though occasional interlocking adds subtle character, and the texture is moderately coarse and even. Regional variations in color and streaking further enhance its appeal for those seeking unique and robust timber.
Applications of Grey Ironbark Timber
Grey Ironbark’s reputation for strength and durability makes it a versatile material for both structural and aesthetic purposes. In engineering, it is used for wharf and bridge construction, railway sleepers, cross-arms, poles, piles, and mining timbers. The timber’s robustness also lends itself to general construction, including house framing with unseasoned timber, and cladding, flooring, linings, and joinery when seasoned and dressed. Beyond construction, Grey Ironbark has historical significance in boatbuilding, where it has been utilized for keels, frames, and planking, even in icebreaker ships. It is also popular in landscaping for fencing and retaining walls, as well as in crafting agricultural machinery, mallet heads, and sporting goods like croquet mallets and bowling pins.
Workability of Grey Ironbark Timber
While Grey Ironbark is exceptionally durable, its density of 1120 kg/m³ makes it a challenging timber to work with. It is slow to dry and requires careful handling during processing to avoid surface checking. Despite its density, the timber can be machined effectively with the right tools, producing dressed surfaces with a characteristic steely sheen. It is well-suited for sanding and polishing, which brings out its rich colors and texture, making it an excellent choice for decorative applications like outdoor furniture and fine joinery.
Durability of Grey Ironbark Timber
Grey Ironbark is classified as a Class 1 timber for both in-ground and above-ground applications, offering exceptional resistance to decay, termites, and borers. Its long lifespan, exceeding 40 years in most structural uses, makes it a reliable and sustainable choice for even the most demanding environments.
Origin and Availability of Grey Ironbark Timber
Native to the coastal regions of New South Wales and southern Queensland, Grey Ironbark is widely regarded as one of Australia’s finest hardwoods. While commonly available in large sizes for structural use, it can also be supplied in custom sizes for a range of applications. The commercial prevalence of Eucalyptus paniculata ensures that Grey Ironbark remains a dependable option for both traditional and modern projects.
Very Low | Low | Medium | High | Very High | |
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Tangential : | 7.50% | ||||
Radial : | 4.70% | ||||
Unit Movement Tangential: | 0.39% | ||||
Unit Movement Radial: | 0.31% |
Very High | High | Reasonably High | Medium High | Medium | Reasonably Low | Low | Very Low | |
Unseasoned: | S1 | S2 | S3 | S4 | S5 | S6 | S7 | S8 |
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Seasoned: | SD1 | SD2 | SD3 | SD4 | SD5 | SD6 | SD7 | SD8 |
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Structural No. 1 | Structural No. 2 | Structural No. 3 | Structural No. 4 | Structural No. 5 | |
Unseasoned: | F22 | F22 | F17 | F14 | F11 |
Seasoned: | F34 | F34 | F27 | F22 | F17 |
Seasoned: | 1106kg/m3 |
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Unseasoned: | 1170kg/m3 |
Very High | High | Reasonably High | Medium | Low | Very Low | |
Unseasoned: | J1 | J2 | J3 | J4 | J5 | J6 |
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Seasoned: | JD1 | JD2 | JD3 | JD4 | JD5 | JD6 |
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White, yellow, pale straw to light brown | Pink to pink brown | Light to dark red | Brown, chocolate, mottled or streaky | |
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Modulus of Rupture - Unseasoned: | 121 MPa |
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Modulus of Rupture - Seasoned: | 185 MPa |
Modulus of Elasticity - Unseasoned: | 19 GPa |
Modulus of Elasticity - Seasoned: | 23 GPa |
Maximum Crushing Strength - Unseasoned: | 63 MPa |
Maximum Crushing Strength - Seasoned: | 97 MPa |
Impact - Unseasoned: | 27 J |
Impact - Seasoned: | 25 J |
Toughness - Unseasoned: | Medium - 15 - 24 Nm |
Toughness - Seasoned: | Medium - 15 - 24 Nm |
Hardness - Unseasoned: | 11 |
Hardness - Seasoned: | 16 |
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: | Not Susceptible |
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Lyctid Borer Susceptibility - Other: | |
Termite Resistance: | Resistant |
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
EFH Spread-of-Flame Index: | |||||||||||
EFH Smoke-Developed Index: |
Critical Radiance Flux - Lower: | >2.2 and <4.5 |
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Critical Radiance Flux - Higher: | ≥4.5 |
Smoke Development Rate: | <750 |
1 - non-combustible | 2 - reasonably non-combustible | 3 - slightly combustible | 4 - combustible | |
Fire Properties Group |
Average Specific Extinction Area: | <250 |
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Bushfire Resistance: | BAL 12.5 and 19 – All AS3959 required applications |