Jarrah | Eucalyptus marginata

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

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.

Properties

Shrinkage

Very Low Low Medium High Very High
Tangential:          
7.4
Radial: 4 - 5
Unit Movement: 0.3 %

Strength Group

Very High High Reasonably High Medium High Medium Reasonably Low Low Very Low
Unseasoned:S1S2S3S4S5S6S7
Seasoned:SD1SD2SD3SD4SD5SD6SD7SD8

Stress Grade

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

Unseasoned: 1170 kg/m3
Seasoned: 800 kg/m3

Joint Group

Very High High Reasonably High Medium Low Very Low
Unseasoned:J1J2J3J4J5J6
Seasoned:JD1JD2JD3JD4JD5JD6

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: 68
Modulus of Rupture - Seasoned: 112
Modulus of Elasticity - Unseasoned: 10
Modulus of Elasticity - Seasoned: 13
Maximum Crushing Strength - Unseasoned: 36
Maximum Crushing Strength - Seasoned: 61
Impact - Unseasoned: 13
Impact - Seasoned: 10
Toughness - Unseasoned: Low - up to 15 Nm
Toughness - Seasoned: Low - up to 15 Nm
Hardness - Unseasoned: 5.7
Hardness - Seasoned: 8.5

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: 8.5
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
Number:
Average Specific Extinction Area: <250
Bushfire Resistance: 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.

Description

Botanical Name: Eucalyptus marginata
Preferred Common Name: Jarrah
Species Type: Hardwood

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.

Common Form

Sawn, Veneer

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

Availability - Further Information

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

Applications

  • 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 Rails and Balustrades

    This guide 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.

  • 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.

  • 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 Rails and Balustrades

    With its natural beauty and inherent strength, timber is a popular material choice in internal balustrade construction. 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.

  • 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 Joinery Products

    Timber joinery products offer a classic, unique and stylish touch to any interior design.

  • Timber 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.

  • 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.

  • 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.

Case Studies

  • Joy Yeo Performing Arts Centre, Roseville College

    In Roseville College's Joy Yeo Performing Arts Centre, the use of Jarrah and Rose Gum pleases the ear as well as the eye.

    Applications: Flooring, Internal Paneling,

  • National Portrait Gallery, Canberra

    Jarrah, Spotted Gum, Blackbutt and Victorian Ash play an essential role in the National Portrait Gallery’s expression of Australian identity.

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

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