Keruing

Keruing is a hardwood native to South East Asia and used in a wide variety of internal and external applications.

Other Names

Apitong, Hagakhak, Panau, Dau, Eng, Yang, Keruwing, Kruen, Kujun, Klalar, Keroewing, Iagan,Dipterocarpus, Dipterocarpus alatus, Dipterocarpus apterus, Dipterocarpus baudii, Dipterocarpus cornutus, Dipterocarpus costulatus, Dipterocarpus crinitus, Dipterocarpus dyeri, Dipterocarpus exalatus, Dipterocarpus gracilis, Dipterocarpus gradiflorus, Dipterocarpus indicus, Dipterocarpus lowii, Dipterocarpus macrocarpus, Dipterocarpus obtusifolius, Dipterocarpus sublamellatus, Dipterocarpus turbinaturs. Dipterocarpus verrucosus, Dipterocarpus warburgii

Botanical Name

Dipterocarpus confertus

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Keruing is the name given to the timber yielded from more than 70 species of the genus Dipterocarpus. This group of large hardwoods is indigenous to South East Asia, where the species are harvested from managed forests with regeneration programs.

    Across the entire species, a wide variety of heartwood hues are available, including deep-pink, orange-pink and purple-red. The most common heartwood is red-brown. Sapwood is usually lighter, sometimes with yellow or grey tinges. The wood darkens with age and features a generally straight, or shallowly interlocked grain, sometimes with a stripe figure on the radial surface. Texture varies between species from fine to coarse but is always uniform.

    Keruing timber is low maintenance, hardwearing and ideal for outdoor furniture use. The wood is strong and classified as durable, making it useful for construction purposes. Other common uses include internal flooring, protected framing and boards, internal joinery and mouldings, lining, paneling and framework. Preservative-treated material is used for poles, piles, sleepers and cross-arms.  It is often used as a cheaper alternative to oak for heavy construction, decking, vehicle building and sleepers, and it is also in plywood.

    Where other timbers may require curing, keruing is completely cured and ready for immediate use with no risk of leaching, bleeding or leach sap. It contains oleo-resins and will exude it onto surfaces during drying or when exposed to heat or sunshine when in use; gums may also cause problems in machining.

    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.
    5.30%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    2.40%

    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.
    0.53%

    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:

    780kg/m3

    Unseasoned:

    950kg/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.
    82

    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.
    137

    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.
    14

    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.
    72

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

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

    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.
    4.7

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    5.6

    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.

    Not 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.
    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: 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

    Across this entire species of keruing, a wide variety of heartwood hues are available, including deep-pink, orange-pink, and purple-red. The most common heartwood is red-brown. Sapwood is usually lighter, sometimes with yellow or grey tinges. The wood darkens with age and features a generally straight or shallowly interlocked grain, sometimes with a stripe figure on the radial surface. Texture varies between species from fine to coarse but is always uniform.

    Common Applications

    Keruing timber is strong and classified as durable, making it useful for construction purposes. Other common uses include internal flooring, protected framing and boards, internal joinery and mouldings, lining, paneling, and framework. Preservative-treated material is used for poles and piles.

    Workability

    Keruing may be difficult to work when dry due to the presence of both silica and resin. Sanding dust can irritate the skin. The wood nails satisfactorily but glues variably.

    Where other timbers may require curing, keruing is completely cured and ready for immediate use with no risk of leaching, bleeding or leach sap. It contains oleo-resins and will exude it onto surfaces during drying or when exposed to heat or sunshine when in use; this high resin content makes it a poor base for coating. Gums may also cause problems in machining and it is unsuitable for steam bending.

    Origin of timber
    Asia
    SE Asia, Indonesia, Malaysia, Sabab, Sarawak, Brunei, Pakistan, Philippines, India
    Keruing is occasionally imported to Australia.
    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 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.

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