Outdoor Timber Decking

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Ironwood is a commonly used marketing name for hard wood. In Singapore context ironwood is referring to a type of wood called Belian, which can be found in Indonesia.

Belian trees may reach a height of 100ft with trunk diameters of exploitable trees up to 36” (90cm). This durable sinker wood seasons slowly becoming black with age and according to the book “The Prehistory of Sabah” by Tom & Barbara Harrison, it is said that “in the open, in this climate(tropical), only the hardest wood, such as belian, lasts more than a century, never two.” The hardwood is rated as very durable with a service life of 50-100 years in ground contact being reported immune to termite attacks. A service life of 20 years and more for marine work in tropical waters is reported. Belian is normally used for heavy construction, marine work, boatbuilding, piling, printing blocks, specialty furniture, industrial flooring, roofing shingles and tool handles. This wood has a tendency for checking and splitting but with due care, this problem may be rectified easily.


The Standard Malaysian Name for the timber of Eusideroxylon zwageri(Lauraceae). Occasionally, the tree is known as tambulian in Sabah, while the European trade name for this timber is Borneo ironwood. The timber is monotypic. The sapwood is bright yellow when fresh, darkens on exposure and is sharply defined from the heartwood which is light brown to almost bright yellow when fresh and darkens on exposure to deep reddish brown, becoming very dark brown or almost black with age.

Also know asn Belian (Brunei); Borneo Ironwood (European Union);Belian, Onglen, Tebelian, Tulian and Ulin (Indonesia); and Biliran, Sakian and Tambulian (Philippines).


The timber is exceptionally hard and heavy and it has been classified under Heavy Hardwood with a density of 835-1,185 kg/m3 air dry.


The timber is one of the most durable in the world.


The heartwood is extremely resistant to preservative treatment.


Texture is moderately fine to fine and even with grain fairly straight or shallowly interlocked.


The timber falls into Strength Group A (Burgess, 1958) or SG 2 (MS 544:Part 2:2001).


It is easy to work despite its high density and produces a smooth and often lustrous surface.


The timber seasons slowly with a tendency for checking and splitting.


Shrinkage averages 4.5%.


The timber is suitable for all heavy constructional works, marine construction, boat construction, fence posts, heavy duty industrial flooring, decking, fender supports, telegraphic and power transmission posts and cross arms, mallets, shingles, columns (heavy duty) and other works where high strength and durability are required.


  1. Burgess, H.J. 1958. Strength Grouping of Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 25. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 15 pp.
  2. Menon, P.K.B. 1986. Uses of Some Malaysian Timbers. Revised by Lim, S.C. Timber Trade Leaflet No. 31. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 48 pp.
  3. MS 544:Part 2:2001. Code of Practice for the Structural Use of Timber: Permissible Stress Design of Solid Timber.
  4. Wong, T.M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S.C. & Chung R.C.K. Malayan Forest Records No. 30. Forest Research Institute Malaysia, Kuala Lumpur. 201 pp.

Chengal Wood:

Chengal Wood is well known in Singapore market. It has been used for heavy outdoor application since… long time ago.


The Standard Malaysian Name for the timber of Neobalanocarpus heimii(Dipterocarpaceae). Vernacular names applied include penak (Peninsular Malaysia). The name chengal is so popular, that many other species have been given vernacular names bearing the name chengal.Neobalanocarpus is a monotypic genus. The sapwood is light yellow and sharply defined from the heartwood, which is light yellow-brown with a distinct green tinge, darkening on exposure to dark purple-brown or rust-red.

Also known as Chengal (Brunei); and Chan Ta Khien, Chi-ngamat, Takian Chan and Takian Chantamaeo (Thailand).


The timber is a Heavy Hardwood with a density of 915-980 kg/m3 air dry.


The timber is classified as naturally durable and is normally very resistant to termite attack and fungal infestation. Under graveyard test conditions, untreated specimens of size 50 mm x 50 mm x 600 mm lasted 9 years. Treated specimen of the same size and test conditions lasted about 19 years. Untreated railway sleepers of size 238 mm x 125 mm x 1,950 mm laid under severe environmental conditions gave an average service life of 19 years.


This timber has been classified as moderately difficult to treat.


Texture is fine and even, with shallowly to deeply interlocked grain.


The timber falls into Strength Group A (Engku, 1988b) or SG 1 (MS 544:Part 2:2001).

Strength Properties of Chengal


It is slightly difficult to resaw and is easy to moderately easy to cross-cut. Planing is easy and the planed surface produced is smooth.

Machining Properties of Chengal


Nailing property is rated as very poor.


The timber seasons slowly with moderate end-checking and surface-checking as the main sources of degrade. 13 mm thick boards take approximately 5 months to air dry, while 38 mm thick boards take 6 months.


Kiln Schedule B is recommended. The timber dries very slowly and is extremely prone to surface-checking. 25 mm thick boards take approximately 30 days to kiln-dry from 50% to 10% moisture content.

Kiln Schedule B 


Shrinkage is fairly low, with radial shrinkage averaging 1.1% and tangential shrinkage averaging 2.6%.


Small pin-holes, caused by ambrosia beetles boring into the living trees, are a common and characteristic defect of chengal. These small holes are often numerous, but although unsightly, they are only in exceptional cases sufficiently numerous to impair the strength of the timber. These ambrosia beetles die when the timber is seasoned and thus the damage is restricted almost entirely to that which occurs in the green timber. Big trees of chengal are sometimes hollow at the centre and badly attacked by large borers, and occasional trees are seriously infected by a fungus (Fomes spp.), which initially gains entry through broken branches or other wounds and eventually reduces the timber to a dark pulpy condition. With the exception of pin holes, the timber of chengalis free from knots and other defects characteristic of sawn timber.


The timber is suitable for all forms of heavy construction, railway sleepers, heavy duty furniture, laboratory benches, bridges, marine construction, boat building, telegraphic and power transmission posts and cross arms, piling, mallets, flooring (heavy traffic), decking, vehicle bodies (framework and floor boards), fender supports, cooling towers (structural members), staircase (balusters, carriages, handrails, newels, risers, stringers, treads, bullnoses, round ends and winders), columns (heavy duty), door and window frames and sills, tool handles (impact), carving works and other uses where strength and durability are required.

Kumasi Wood:

100% natural. The timber is free of resin and other chemicals. It is manufactured without the use of any chemical substances. Kumasi looks like genuine, beautiful wood, because it is real wood, with real character that’s been modified adding lasting value and charm to your home.

It is ecological. It’s harmless to human beings and living species. It is environmental friendly, healthy, recyclable, strong, durable and long lasting. It is produced from sustainable forests.

It is durable. Maintains durability in all weather conditions. It is longer lasting than Kiln Dried wood. Its low humidity prevents decay and fungal growth. remains straighter and smoother longer,• and is three times more resistant to shrinking and swelling than untreated wood.

It is stable. It is 90% less likely to bend and twist compared to wood which has not been modified. Its durability is enhanced by minimizing any movement.

It is homogeneous. As a result of the process the colour of the wood becomes homogeneous. It’s retention of polish and paint is increased compared to regular wood.

It is isolated. It provides 25% more sound and heat isolation than non-modified wood.

It is safe. It is 30% more fire resistant than normal timber.

Safe against infestation. Insect formation is completely prevented as a result of the removed moisture content through high heat treatment.



How to maintain a deck? As with all materials, years of sun exposure will slowly fade the finish, so when it happens. You are ready to refresh your deck with the most options:

  • Refresh: Simply use water with a mild, pH-neutral cleaner to spruce up the appearance of your Perennial Wood deck.
  • Re-Stain: Add a fresh coat to your deck, reinvigorating your original color.
  • Re-color: Strip off your old stains and changes the color. Refinishing won’t affect the wood’s ability to endure

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