Mahogany, Red

Red mahogany is an Australian hardwood with a fine grain and stunning red colouring used for engineering applications, construction, furniture and turnery.

Other Names

Red Stringybark, Daintree Stringybark (Qld), Red Messmate (Qld), Eucalyptus resinifera

Botanical Name

Eucalyptus pellita

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Red mahogany is a hardwood with a fine grain and attractive red colouring. It is a versatile wood suitable for engineering applications and for use in construction. Due to its figuring, it is prized for furniture and turning. Red mahogany has become a prestigious timber owing to its durability, termite resistance and distinctive colouring.

    Different species of red mahogany grow in different regions of Queensland, New Guinea and Irian Jaya. E. resinifera occurs from Jervis Bay in New South Wales to Coen in Queensland. E. pellita occurs from north of Townsville to Iron Range on Cape York Peninsula and through areas from Gladstone in Queensland to southern coastal New South Wales.

    Trees of this species reach a height of 40-45m with 1-1.5m trunk diameter. The bark is fibrous, shallow to coarsely fissured, and persists on even the small branches. Different species have differently coloured bark; E. resinifera being greyish to reddish-brown and E. pellita being reddish-brown to brown.

    Red mahogany is a dense, durable timber. The heartwood ranges from red to dark red, but sapwood is distinctively paler. The even grain is generally moderatley textured, displaying the occasional gum vein, and at times the grain is interlocked producing an attractive figure.

    The density of the timber varies depending on its source; plantation grown 8.5 year-old timber has 70% of the density of natural grown timber, creating some variance in hardness. Uses of red mahogany have included wharf and bridge construction, railway sleepers and in mining timbers. It is used for a wide range of interior and exterior purposes in general construction and can be made into indoor and outdoor furniture. Other uses include boat building, coach, vehicle and carriage building and structural plywood.  

    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.
    6.30%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    3.90%

    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.
    0.34%

    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.
    0.27%

    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:

    F27

    F17

    F14

    F11

    F8

    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:

    950kg/m3

    Unseasoned:

    1200kg/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.
    90

    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.
    138

    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.
    14

    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.
    17

    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.
    52

    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.
    76

    Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    16

    Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    16

    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.
    9.0

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    12

    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.

    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

    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

    Red mahogany is a beautiful timber, displaying a range of deep red and pale pink hues. The grain is uniform and somewhat course and can be interlocked, producing a stunning figure. Generally the heartwood is a deep, rich red in colour but it may be lighter in younger material. The timber’s sapwood is paler and clearly distinct from the heartwood. Tight gum veins, gum deposits and pinhole borer discolouration occasionally augment the appearance of the timber and pencil streak is common.

    Common Applications

    Red mahogany's durability, hardness and distinctive colouring make it one of the most versatile of timbers. The engineering applications of red mahogany as a sawn and round timber can be seen in wharf and bridge construction, railway sleepers, cross arms, poles, piles, mining timbers. As sawn timber for construction purposes it is used in general house framing, cladding, internal and external flooring, linings, joinery, fencing, landscaping, including use in retaining walls, although it is less ideal for use in contact with the ground. One of its finest uses is for decorative purposes, in the manufacture of quality indoor and outdoor furniture. It is also prized for turning. Red mahogany's versatility can be seen further in its use in boat building (keel and framing components, planking), coach, vehicle and carriage building, agricultural machinery and in structural plywood.  

    Workability

    For a dense timber that is very hard, red mahogany is relatively easy to work and machine with both hand and power tools. It can be satisfactorily dried using conventional air and kiln seasoning. The heartwood is highly resistant to termites and the softwood susceptible to lyctid borer. The sapwood readily accepts preservative impregnation but penetration of heartwood is negligible using currently available commercial processes. No difficulty has been experienced when using standard fittings and fastenings. As with most highly dense species, machining and surface preparation should be done immediately before gluing. The species holds both nails and staples well. Finishing the timbers is possible through a range of methods. The timber accepts paint and stain and is one of the best eucalypts for painting since the wood has good resistance to surface checking. It develops a lovely finish when polished.  

    Origin of timber
    NSW
    Readily Available
    NSW
    Red mahogany is available only in limited quantities, due to heavy logging in the past. Early research trials suggest that future supplies of plantation-grown E. pellita will be available from northern Queensland on suitable soils and where the mean annual rainfall exceeds 900 mm.
    a wood fence with trees in the background

    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.
    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 close-up of a building

    Cladding, External

    The natural appeal, versatility and strength of timber makes it the superior choice for external cladding. Through specification, planning, design and finishing processes, timber cladding not only creates a building of superior strength, acoustic and thermal performance but also creates a place of beauty, style and natural appeal.
    a room with tables and chairs

    Structural Timber Poles

    Timber poles are utilised in structural construction to provide support for gravity loads and resistance against lateral forces. Not only serving a structural function, timber poles provide many aesthetic benefits, with their use in construction often complementing architectural designs aimed at harmonisation with the natural environment.
    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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