Box, Brush

Brush box is a medium to large sized Australian hardwood that grows along the edges of the rainforest areas of New South Wales and Queensland. It is used for a variety of applications including flooring, cladding and bridge decking.

Other Names

Pink Box, Scrub Box, Tristania conferta

Botanical Name

Lophostemon confertus

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Brush box is a medium to large sized Australian hardwood that occurs along the edges of the rainforest areas of the central coast of New South Wales to Bowen in Queensland.

    Its heartwood can vary in appearance, from a greyish pink through to a reddish brown, while the sapwood is usually paler in colour. Brush box has a fine and even texture with an interlocking grain – a feature that is appealing for appearance-based applications such as timber flooring, but can cause significant distortion during drying.

    Brush box has a poor workability in part due to its density, interlocked grain and the presence of silica. It does however provide good resistance to wear and splintering. The natural waxiness may cause problems with some adhesives but provides a very good base for paints and stains. Brush box is not suitable for steam bending.

    Brush box is used for a variety of applications including flooring, cladding, paneling and some structural applications.  It is generally available for use in New South Wales and Queensland.

     

    Shrinkage

    Very Low Low Medium High Very High
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    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.
    9.70%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    4.40%

    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.
    0.38%

    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:

    F17

    F14

    F11

    F8

    F7

    Seasoned:

    F27

    F22

    F17

    F14

    F11

    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:

    890kg/m3

    Unseasoned:

    1190kg/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.
    77

    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.
    121

    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.
    12

    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.
    15

    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.
    39

    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.
    64

    Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    14

    Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    12

    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.
    Medium - 15 - 24 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.
    Medium - 15 - 24 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    7.8

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    9.1

    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.

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    (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.

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

    Not 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
    Appearance

    Brush box has a fine, interlocked grain and even texture with the heartwood ranging from greyish pink through to a reddish brown, while the sapwood is usually paler in colour. It is free of gum veins. The grain is especially appealing for appearance-based applications such as flooring.

    Common Applications

    Brush box is used for a variety of applications, which consist mainly of flooring, cladding, paneling and some structural applications. Brush box has also been used for mallets, mauls, handles, shuttles, turnery, wharf and bridge decking, carriage building, weatherboarding, boat building and wedges.

    Workability

    Brush box has poor workability in part due to its density, interlocked grain and the presence of silica. Nailing and screwing brush box may cause splitting.
    The silica content can cause major problems for tool edges, while the natural waxiness, known as arjunolic acid, may cause problems with some adhesives but provides a very good base for paints and stains.
    Box box is not suitable for steam bending. It does however provide good resistance to wear and splintering.

    Origin of timber
    NSW
    Readily Available
    NSW
    Brush box is limited in availability in its states of origin and rarely available in the other states and territories.
    Source of timber
    Native Forest
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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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