Jarrah

Jarrah is an Australian hardwood renowned for its versatility, durability and strength in a wide range of interior and exterior applications.

Botanical Name

Eucalyptus marginata

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Jarrah is a unique Australian hardwood renowned for its versatility. Its durability and strength make it an ideal timber for a range of structural and design applications, with timbers that display colours ranging from deep red to blonde.

    Jarrah trees grow on the iron and aluminium rich plains of south-western corner of Western Australia, from the ranges east of Perth down to Albany. They are slow growing, their roots often reaching to great depths in search of nutrients and water. Their long, straight trunks, can grow up to 40 metres tall and 2 metres in diameter, creating beautifully coloured and grained timbers. The bark is rough with a fibrous texture, and covers the entire trunk and smallest branches. The trees do not germinate from seed, but from lignatubers, large underground swellings that store energy and nutrients, allowing young trees to regenerate after bushfires.

    Jarrah timbers reflect the hues of the Western Australian landscape. The heartwood varies in colour from rich reds to browns, while sapwood ranges from a pale yellow to orange. The texture of the timber is moderately coarse and even-textured grain, although some interlocked, wavy grain may feature, creating interesting fiddle-back figure. This makes it an appealing architectural and design material.

    Jarrah's natural properties include a high resistance to weather, rot, termites and even marine borers, making it valuable for a range of outdoors uses. Its density also makes it fire resistant. It can be used in wharf and bridge construction, railway sleepers, cross arms, poles and piles. Construction applications include general house framing, flooring, linings, joinery and fencing. Jarrah's decorative qualities make it prized for use in furniture, turnery, joinery and parquetry.

    Jarrah makes a versatile and aesthetically pleasing decking board based on its natural durability and bushfire resistance properties (BAL 12.5 and 10 per all AS3959 applications; BAL 29 when used in conjunction with non-combustible wall cladding and enclosed subfloor. A copy of the EWFA Certificate of assessment can be downloaded here.

    Shrinkage

    Very Low Low Medium High Very High
    Check mark Check mark Check mark

    Tangential : Provides a simplified rating for tangential shrinkage. This is the measure of the percentage reduction in dimension from the unseasoned to 12% moisture content condition.
    7.40%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    4.80%

    Unit Movement Tangential: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.
    0.30%

    Unit Movement Radial: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.
    0.24%

    Strength Group Strength groups are given for unseasoned (S1-S7) and seasoned (SD1-SD8) timber in accordance with AS 2878. S1 and SD1 yield the highest strength and stiffness whereas S7 and SD8 yield the lowest.

    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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    Stress Grade A stress grade is defined in AS 1720 as the classification of timber for structural purposes by means of either visual or machine grading. The stress grade indicates the basic working stresses and stiffnesses to be used for structural design purposes. Measured in MPa.

    Structural
    No. 1    		 Structural
    No. 2    		 Structural
    No. 3    		 Structural
    No. 4    		 Structural
    No. 5

    Unseasoned:

    F14

    F11

    F8

    F7

    F5

    Seasoned:

    F22

    F17

    F14

    F11

    F8

    Density per Standard Seasoned density is based on moisture content of 12%. Unseasoned density is an approximation as it depends on the moisture content at the time of measurement. Measured kg/m3.

    Seasoned:

    820kg/m3

    Unseasoned:

    1100kg/m3

    Joint Group The joint group is a classification of the strength of a species in joint design. The values are from 1 (very high strength) to 6 (very low strength).

    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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    Colour The colour of seasoned heartwood can vary between species and often within a species. The information provided should be used as a general guide only. In most cases, the colour of sapwood is either a lighter shade of the heartwood or a white/cream colour.

      White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
       
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    Mechanical Properties

    Modulus of Rupture - Unseasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.
    68

    Modulus of Rupture - Seasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.
    112

    Modulus of Elasticity - Unseasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.
    10

    Modulus of Elasticity - Seasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.
    13

    Maximum Crushing Strength - Unseasoned:

    Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.
    36

    Maximum Crushing Strength - Seasoned: Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.
    61

    Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    13

    Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    10

    Toughness - Unseasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.
    Low - up to 15 Nm

    Toughness - Seasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.
    Low - up to 15 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    5.7

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    8.5

    Durability

    Low Moderate Reasonably High High
    (0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)

    In-Ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

    		 Check mark
    (0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)

    Above ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

    		 Check mark
    (0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)

    Marine Borer Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to marine borer attack.

    		 Check mark

    Lyctid Borer Susceptibility: Indicates whether a species is susceptible (S) or not susceptible (NS) to lyctid borer attack.

    Susceptible

    Lyctid Borer Susceptibility - Other:

    Termite Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to termites.

    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: A measure of the tendency of a material to ignite measured on a scale of 0 – 20. An index of 0 indicates that the material did not ignite during the 20 minutes that the test takes. An index of 20 indicates that the material ignited in the first minute.
    0 1 2 3 4 5 6 7 8 9 10

    EFH Spread-of-Flame Index: This is a material's propensity to burn rapidly and spread flames based on a scale of 0 to 10 where 0 means that the materials will not cause flames to reach the ceiling and 10 indicates that the material could be expected to cause flames to reach the ceiling of a room within 10 seconds of ignition.

    EFH Smoke-Developed Index:This is a measure of the concentration (measured by optical density) of smoke a material emits as it burns. It is based on an arbitrary scale of 0 to 10. The higher the index, the greater the hazard from smoke is likely to be.

    Critical Radiance Flux - Lower: This measures the radiant (heat) energy required to sustain burning. It is used in Australia to regulate floor coverings. The requirements are set out in BCA Specification C1.10a, providing CRF values for floor coverings based on Class of building, the location within the building (general use or use in fire isolated exits) and whether or not the building is sprinkler protected or not. CRF is measured in kW/m2.

    >2.2 and <4.5

    Critical Radiance Flux - Higher: This measures the radiant (heat) energy required to sustain burning. It is used in Australia to regulate floor coverings. The requirements are set out in BCA Specification C1.10a, providing CRF values for floor coverings based on Class of building, the location within the building (general use or use in fire isolated exits) and whether or not the building is sprinkler protected or not. CRF is measured in kW/m2.

    ≥4.5

    Smoke Development Rate: This is the speed at which smoke increases as determined by testing flooring materials in accordance with AS ISO 9239.1. The rate is expressed in terms of percent/minutes. For buildings not protected with a sprinkler system, a maximum smoke development rate of 750 percent/minute applies.
    <750
    1 - non-combustible 2 - reasonably non-combustible 3 - slightly combustible 4 - combustible

    Fire Properties Group
    Number:

    Average Specific Extinction Area: This value is determined by the volume of smoke measured over the mass loss of the tested sample per test carried out in accordance with ‘Cone Calorimeter Test’ AS/NZS 3837. It is measured in units of m2/kg.
    <250

    Bushfire Resistance: Naturally bushfire-resisting timbers are those with inherent bushfire-resisting properties. Some species have been tested and a number are in the process of being tested and are measured by Bushfire Attack level (BAL). BAL -12.5: Ember attack, BAL – 19: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kWm3, BAL – 29: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kWm3.
    BAL 12.5 and 19 – All AS3959 required applications, BAL 29 - Decking (in conjunction with non-combustible wall cladding and enclosed subfloor). A link to the Certificate of Assessment is under the Overview tab.
    Appearance

    Jarrah is renowned for its rich red colours that deepen over time. The heartwood ranges from deep browns to burgundy hues. Jarrah sapwood exhibits shades from pale yellow to pink-orange. The timber displays a moderately coarse and even textured grain. The occasional incidence of wavy and interlocking grain produces some samples with a sought after fiddle-back figure.

    Common Applications

    Jarrah has a history of use in engineering applications such as wharf and bridge construction, railway sleepers, cross-arms, piles, and for road bases. Its structural applications include posts and poles, framing, flooring, lining, decking and cladding.

    A highly versatile timber, jarrah can also be used for woodturning, making it useful in the manufacture of high quality indoor furniture and weather resistant outdoor furniture that stands the test of time. The wood is also prized by luthiers for creating guitar and banjo necks.

    Workability

    Jarrah is easiest to work when it is green. Once seasoned, it is relatively easy to work, despite its density, if tools are maintained in sharp condition. Jarrah timber can be machined and turned easily. When using it in a planer, the blade must be set to 15 degrees to give the best surface quality. It can be glued and satisfactorily steam bent, but care must be taken when using nails, due to the density. Jarrah timbers readily accept paint, stain and polish.

     

    Origin of timber
    WA
    Readily Available
    WA
    Jarrah can only be sourced from old growth and native forest regrowth in Western Australia, where it is more commonly available. Many of these forests are now reserved and little to no jarrah is currently grown in commercial plantations. This limits supply and Australia grows few other readily available species with jarrah's distinctive colour and character. While some recycled material is available, this is also a restricted resource as it relies on the demolition of existing buildings.
    Source of timber
    Native Forest
    a kitchen with wooden cabinets and a countertop

    Joinery

    Timber joinery offers a classic, stylish touch to any interior or exterior space.
    a reception desk in a building

    Panelling, Interior

    Timber panelling creates interiors as warm as they are stylish. Commonly using an MDF or plywood substrate, internal timber paneling is natural and versatile and comes as either solid natural timber panels or as sheets of engineered wood products
    a deck with a pool and a deck with a couch and a bench

    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.
    a close-up of a wood sculpture

    Mouldings

    Mouldings are extremely versatile and durable, enhancing the aesthetics of any interior and functioning as the icing on the cake for designs with a focus on beauty and splendour.
    a wooden fenced hillside with plants and a fenced yard

    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.
    a wooden stairs with railings

    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.
    a staircase with a hole in the ground

    Rails and Balustrades, Interior

    With its natural beauty and inherent strength, timber is a popular material choice for internal balustrades. Commonly built from treated softwoods and durable hardwoods, interior balustrades and handrails are typically finished with a clear lacquer to generate the most natural result.
    a staircase in a building

    Stairs, Interior

    Timber is the material of choice for designers seeking internal staircases of strength, beauty and durability.
    a patio with a deck and chairs

    Pergolas

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

    Rails and Balustrades, Exterior

    This provides general information on member sizes, connections and suitable materials for construction of handrails and balustrades in external applications. Commonly built from treated softwood and durable hardwoods, they can be finished with a wide variety of paints or stains, creating balustrades that with the right care and attention, will comfortably withstand the elements for decades to come.
    a glass building with a wood deck

    Windows

    With natural aesthetic appeal, versatility and sound structural performance, timber provides excellent window joinery design options. Whether stained to bring out natural tones, or painted to compliment particular décors, timber windows can be tailored to suit a huge variety of styles and can be installed into any type of building.
    a room with benches and paintings on the wall

    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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