Teak

Scientific name

Tectona grandis. Family: Verbenaceae.

Local names

Djati, jati (Indonesia), kyun (Myannmar), sagwan (India), teck, mai sak (Thailand), giati (Vietnam), teca (Brazil).

Description and natural occurrence

A medium to tall hardwood attaining 45 m on favourable sites but more usually producing a 15 m bole. The stem is irregularly shaped and grooved and the characteristic leaves are very large. Stem diameter averages 1.0 m but can attain up to 2.4 m according to locality and conditions of growth.

One of the most well known world timbers, teak occurs naturally in the monsoon forests of India, Myanmar, Thailand and Vietnam. Plantations of the species have been established in Indonesia, Papua New Guinea, Africa, Solomon Islands, Fiji and the West Indies.

Wood appearance

Colour. The heartwood is generally golden brown but varies from grey-brown to red brown. Longitudinal streaks are often present due to the ring-porous structure of teak. Sapwood is well demarcated, being pale yellow in colour.

Grain. The grain is straight or occasionally interlocked. Texture is uneven varying from smooth to coarse due to its ring porosity.

Wood properties

Density. 670 kg/m3 at 12% moisture content; approximately 1.5 m3 of seasoned sawn timber per tonne.

Strength groups. (S6) unseasoned; (SD6) seasoned.

Stress grades. F4, F5, F7, F8 (unseasoned), F7, F8, F11, F14 (seasoned), when visually stress graded in accordance with AS 2082-1979, Visually stress-graded hardwood for structural purposes.

Joint groups. JD3 seasoned.

Shrinkage to 12% MC. 2.2% (tangential); 1.2% (radial).

Unit shrinkage. Not available.

Durability above-ground. Class 1 - life expectancy over 40 years.

Durability in-ground. Class 2 - life expectancy 15 to 25 years.

Lyctine susceptibility. Untreated sapwood susceptible to lyctid borer attack.

Termite resistance. Resistant.

Preservation. Sapwood can be impregnated with preservatives.

Seasoning. Teak is a slow drying timber with variation in drying rates between individual pieces. However it seasons with little degrade. Some collapse may occur if high temperatures are used.

Hardness. Firm (rated 4 on a 6 class scale) in relation to indentation and ease of working with hand tools.

Machining. The timber is variable but generally works with moderate ease. Presence of silica in some stock causes severe blunting of cutting edges. It is recommended that planing angle be reduced to 20° and that tungsten-carbide tipped saws be used.

Fixing. Pre-boring is recommended when nailing. Holds nails and screws well.

Gluing. As with most timbers of an oily nature, machining and surface preparation should be done immediately prior to gluing.

Finishing. Varnishes, polishes and waxes well. Will readily accept paint and stains.

Uses

Construction. Flooring, decking, framing, boards, cladding, fascias and barge boards.

Decorative. Lining, panelling, turnery, carving, furniture (both indoor and garden), parquetry.

Others. Teak is perhaps best known for its long established use in the boat building industry. It has been extensively used for decking, deckhouses, rails, bulwarks, hatches, weather doors, and planking. Also used for cooperage, pipes and chemical vats.

Identification features

General characteristics

Sapwood. Pale yellow, readily distinguished from heartwood.

Heartwood. Brown to golden brown. Sometimes streaky.

Texture. Non-uniform, moderately coarse, straight grain and greasy feel.

Further reading

Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, 'Forest trees of Australia', 5th edn, CSIRO Publishing, Collingwood Australia.

Bootle, K 2005, 'Wood in Australia: types, properties and uses', 2nd edn, McGraw-Hill, Sydney.

Hopewell, G (ed.) 2006, 'Construction timbers in Queensland: properties and specifications for satisfactory performance of construction timbers in Queensland, Class 1 and Class 10 buildings', books 1 and 2, Department of Primary Industries and Fisheries, Brisbane.

Ilic, J 1991, 'CSIRO atlas of hardwoods', Crawford House Press, Bathurst, Australia.

Standards Australia, 2000, 'AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes', Standards Australia.

Last updated 16 August 2010