Teak

Teak is one of the world’s best-known hardwood timbers. Teak is renowned for its marine applications, including boat building, and a wide variety of decorative uses.

Other Names

Djati, Jati (Indonesia), Kyun (Myannmar), Sagwan (India), Teck, Mai Sak (Thailand), Giati (Vietnam), Teca (Brazil)

Botanical Name

Tectona grandis

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Teak's heartwood is typically golden brown in colour, although grey and red tinges are not uncommon. The sapwood, a pale yellow colour, is clearly distinct. Grain is usually straight, but due to teak's high degree of ring porosity, longitudinal streaks and an uneven texture, ranging from coarse to smooth, are typical. The freshly cut wood can be variable in colour, with blotches and streaks, but prolonged exposure to light ameliorates the more extreme variations. Teak contains an oleoresin which gives the timber a greasy feel, and imparts a distinctive odour to freshly cut material.


    Teak is a firm timber, in general easily worked. However, the timber's relatively high silica content causes severe blunting of cutting edges. For this reason, the use of tungsten-carbide blades is recommended. Teak holds nails and screws well, although pre-boring is recommended when nailing. Gluing sometimes presents difficulties because of the oily nature of the wood, and it is important to bond only freshly dressed surfaces. Teak will readily accept paints and stains. It also varnishes, polishes and waxes well. It is not suitable for steam bending. Sanding dust irritates the skin of some users.

    Teak is well known for its above ground durability, with a life expectancy of greater than 40 years. In-ground life expectancy ranges from 15 to 25 years. Teak exhibits a good resistance to acids, and will not corrode metal fixings. Teak is termite-resistant, although untreated sapwood is susceptible to borer attack.

    Teak is extensively used in boatbuilding for decking, rails, bulwarks, hatches, weather doors, and planking. It is also used for cooperage, pipes, and chemical vats. In general construction it is suitable for flooring, decking, framing, cladding, fascias and barge boards. Decorative uses of teak include indoor and outdoor furniture, parquetry, turnery, carving, lining and paneling.

    Teak occurs naturally in the monsoon forests of India, Myanmar, Thailand and Vietnam. Teak plantations have been established in Indonesia, Papua New Guinea, Africa, Solomon Islands, Fiji and the West Indies.

     

    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.
    1.90%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    1.00%

    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.
    0.19%

    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.
    0.10%

    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:

    F8

    F7

    F5

    F4

    Seasoned:

    F14

    F11

    F8

    F7

    F5

    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:

    680kg/m3

    Unseasoned:

    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

    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.
    80

    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.
    101

    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.
    9.4

    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.
    10.7

    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.
    41

    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.
    58

    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.
    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.
    Low - up to 15 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    4.1

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    4.4

    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.

    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.
    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

    The heartwood of teak is typically golden brown in colour, although grey and red tinges are not uncommon. The sapwood, a pale yellow, is visually distinct. Due to teak's high degree of ring porosity, longitudinal streaks and an uneven grain texture, ranging from coarse to smooth, are commonly present.

     

    Common Applications

    Perhaps best known for its use in boat building, teak has been extensively used for decking, rails, bulwarks, hatches, weather doors, and planking. It is also used for cooperage, pipes, and chemical vats. In general construction it is suitable for flooring, decking, framing, cladding, fascias and barge boards. Decorative uses of teak include indoor and outdoor furniture, parquetry, turnery, carving, lining and paneling.

     

     

    Workability

    Teak is usually relatively easy to work but silica can be present and this will necessitate frequent sharpening of tools. It peels easily and nails satisfactorily but gluing sometimes presents difficulties because of the oily nature of the wood. It is important to have freshly dressed surfaces. Good resistance to acids. Not corrosive to metal fixings. Unsuitable for steam bending because of excessive buckling. Sanding dust is irritating to the skin for some people. White inclusions of calcium oxalate sometimes appear as flecks in the vessels, lowering the value of veneer thus affected.

     

    Origin of timber
    NT
    Bangladesh, Burma, Central America, Fiji, India, Indonesia, NT, PNG, Thailand and Tropical Africa
    Readily Available
    NSW
    Teak is becoming scarce.
    Source of timber
    Plantation
    a large room with rows of chairs

    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.

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