Ironbark, Red

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

Botanical Name

Eucalyptus sideroxylon

Common Form
Sawn
Species Type

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.

Shrinkage

Very Low Low Medium High Very High

Tangential :

6.30%

Radial :

3.50%

Unit Movement Tangential:

0.37%

Unit Movement Radial:

0.27%

Strength Group

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

S8

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:

1050kg/m3

Unseasoned:

1160kg/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:

107

Modulus of Rupture - Seasoned:

149

Modulus of Elasticity - Unseasoned:

15

Modulus of Elasticity - Seasoned:

17

Maximum Crushing Strength - Unseasoned:

53

Maximum Crushing Strength - Seasoned:

79

Impact - Unseasoned:

20

Impact - Seasoned:

13

Toughness - Unseasoned:

High - 25 Nm and above

Toughness - Seasoned:

Medium - 15 - 24 Nm

Hardness - Unseasoned:

10.7

Hardness - Seasoned:

11.9

Durability

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:

Susceptible

Lyctid Borer Susceptibility - Other:

Termite Resistance:

Resistant

Fire Properties

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

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
Number:

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
Appearance

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.

Workability

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
NSW
Readily Available
NSW
Red ironbark is readily available in Australia.
Source of timber
Native Forest
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Joinery

Timber joinery offers a classic, stylish touch to any interior or exterior space.
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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.
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Fencing

When it comes to fencing, timber is a 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 ensure a timber fence provides a natural and lasting property boundary and back drop for years to come.
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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 has 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 beautiful timber retaining wall that will complement its surrounding landscape for years to come.
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Stairs, Exterior

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.
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Stairs, Interior

Timber is the material of choice for designers seeking internal staircases of strength, beauty and durability.
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Pergolas

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

The warmth, strength and natural beauty of timber flooring is enduringly popular in a wide variety of domestic, commercial and industrial applications.

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