Ironbark, Red | Eucalyptus sideroxylon

Red ironbark is a very distinctive Australian hardwood that has been prized for over 200 years for its strength and durability.

Other Names: Mugga, Ironbark


Red ironbark is a handsome Australian hardwood that grows readily from Victoria through the western slopes of NSW into southern Queensland. As one of a very distinctive group of Australian eucalypts, the ironbarks, it can be easily recognised by its hard, deeply furrowed, rough bark ranging from a dark grey to black hue. It has been a preferred structural timber for over 200 years, due to its long-term performance in weather-exposed structural applications.

Red ironbark heartwood is a deep dark red to red-brown. By contrast, its sapwood is a distinctive pale yellow in colour. The timber's texture is fine and even with an interlocked grain. It is extremely hardwearing and highly durable, allowing for wide range of external applications. However the timber is very hard to work, limiting some applications that require fine detailing. It is slow to dry and care needs to be taken to minimise surface checking.

Red ironbark is ideal for engineered structures that require excellent durability and strength, including wharf and bridge members, poles, railway sleepers, mining timbers. The timber is also suitable for all building construction materials from poles, framing, flooring, decking and cladding. Additionally, the wood is suitable for both indoor and outdoor furniture.

The red ironbark tree has a tendency towards piping, where a hollow forms in the trunk's centre trunk and reduces recovery rates and sectional sizes of sawn timber.



Very Low Low Medium High Very High
Radial: 3 - 4
Unit Movement: 0.37 %

Strength Group

Very High High Reasonably High Medium High Medium Reasonably Low Low Very Low

Stress Grade

No. 1
No. 2
No. 3
No. 4
No. 5
Unseasoned: F27 F17 F14 F11 F8
Seasoned: F27 F22 F17 F14 F11

Density per Standard

Unseasoned: 1160 kg/m3
Seasoned: 1050 kg/m3

Joint Group

Very High High Reasonably High Medium Low Very Low


  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: 116
Modulus of Rupture - Seasoned: 118
Modulus of Elasticity - Unseasoned: 15
Modulus of Elasticity - Seasoned: 16
Maximum Crushing Strength - Unseasoned: 59
Maximum Crushing Strength - Seasoned: 70
Impact - Unseasoned: 18
Impact - Seasoned: 13
Toughness - Unseasoned: High - 25 Nm and above
Toughness - Seasoned: Medium - 15 - 25 Nm
Hardness - Unseasoned: 12
Hardness - Seasoned: 14


Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)
(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
Termite Resistance: Resistant

Fire Properties

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
EFH Ignitibility:
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 kW/m2
Critical Radiance Flux - Higher: <4.5 kW/m2
Smoke Development Rate: <750
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, 19 and 29 – All AS3959 required applications


Botanical Name: Eucalyptus sideroxylon
Preferred Common Name: Ironbark, Red
Other Names: Mugga, Ironbark
Species Type: Hardwood


Red ironbark heartwood is a deep red, contrasting dramatically with its distinctive pale yellow sapwood. It has a fine and even texture with an interlocked grain.

Common Applications

Red ironbark is used for heavy engineering, transport, and marine construction, including poles, piles, sleepers, flooring, decking, bridge work, fencing, carriages and wagons, house framing and sporting goods. It is also useful for domestic and non-domestic decks, joinery, furniture and fit outs and expressed hardwood structures.

Common Form



Red ironbark is very hard to work, limiting some applications that require fine detailing. It is slow to dry and care needs to be taken to minimise surface checking.

Origin of Timber


Readily Available


Availability - Further Information

Red ironbark is readily available in Australia.

Source of Timber

Native Forest, Plantation


  • Decking

    Timber decking creates spaces that are functional, practical and aesthetically pleasing. With the right design and care a timber deck will make a valuable addition to any home or business, creating an outdoor living space that will be enjoyed for years to come.

  • Exterior Stairs

    For outdoor applications, timber is one of the leading material choices. Timber use in external staircase applications creates structures of strength and durability, sheathed in a natural beauty that blends seamlessly with the outdoor environment.

  • Fencing

    When it comes to fencing, timber is your natural choice. A material that is durable, strong and reliable it compliments almost every outdoor landscape and environment. Clear specification, detailed installation and appropriate maintenance will see any timber fence provide a natural and lasting property boundary and back drop for years to come.

  • 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.

  • Interior Stairs

    Timber should be the material of choice for designers seeking internal staircases of strength, beauty and durability. The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.

  • Pergolas

    A timber pergola is a practical, functional and attractive way to extend living and entertainment spaces into the outdoors.

  • Retaining Walls (Landscaping)

    When it comes to retaining wall, landscape design and construction, timber is the natural choice. A material that is durable, sturdy and reliable, it boasts natural aesthetics that help it blend seamlessly with the outdoors. Careful consideration during the specification and design process will facilitate the creation of a long lasting, durable and eye catching timber retaining wall that will complement its surrounding landscape for years to come.

  • Shear walls

    Lateral loads such as wind or earthquake on framed timber buildings - either post and beam or stud and joist - need to be resisted and shear walls and diaphragms offer an effective and economical solution.

  • Timber Portal Frames

    For buildings that require large spans and column free interiors, timber portal frames provide one of the most aesthetically pleasing solutions. Utilising modern engineering technology, portal frame design transforms timber into a highly effective, efficient and economical structural product. This application guide provides a comprehensive overview of the process of using timber in the specification, fabrication and erection of portal frame structures.

Case Studies

  • Cranbourne Botanic Gardens Visitor Centre

    The new Visitor Centre in the Australian Garden of the Royal Botanic Gardens, Cranbourne becomes a model of sustainable design the public can apply at home.

    Applications: Decking, Doors, External Cladding, Framing, Windows,

  • Lewis St House, Thornbury

    A stunning residential renovation and addition that uses timber and timber products throughout with a commitment to sustainable design.

    Applications: Architectural Roof Trusses, Doors, External Cladding, Flooring, Framing, Interior Stairs, Windows,

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