Balau timber by sdsdfqw21

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									                                                            Balau timber

Background
Balau comes from Malaysia, mainly from the island of Borneo which is shared by Malaysia and Indonesia. The
government of Malaysia has good control of the harvesting of the timber, which is harvested by contractors in areas
allocated by the state. Each felled log is barcoded according to forestry inspectors. These are then shipped to a mill, which
has to have the correct authentication for every log before it is allowed to be processed. At present there is no FSC
certification for this timber.

Balau grows in the same forests as Meranti, Merbau and Keruing amongst others. All these trees grow to very big sizes,
often up to 2 metres in diameter. There is sufficient quantity of Balau to enable a sustainable supply.
Balau is the chosen wood for outdoor use, in water or exposed to the elements. There is good long term anecdotal
evidence of the longevity of exposed timber even in water, and the long history of public acceptance of the timber in South
Africa can give a specifier peace of mind in this regard. The timber is not chemically treated in any way, as it is not
susceptible to insect attack or detrimental fungal growth in its natural state. Lifespan even in the most arduous conditions
can be expected as over 50 years.
Balau is slightly susceptible to borer beetle when uncut. After felling, borer beetles leave the timber creating very small
holes known as pin hole. This is not a defect and is a natural characteristic of the timber.

The wood is very dense, generally 850 to 1155 kg per cubic metre. (SA Pine is approx 650kg per m3 )

Moisture content
Balau is not kiln dried. Normal practice is to sticker stack the sawn or machined stock for ‘a few months’ in Malaysia,
where the humidity amd ambient temperatures are high. One can expect varying moisture contents on arrival in South
Africa, due to the essentially uncontrolled conditions in the delivery chain (boat to Singapore, then via container ship to us)
The sawn board is subject to a stain inducing mould if close stacked when moist and in hot conditions. For this reason,
and to encourage air drying, it is dispatched stickered.

Moisture contents at the delivery point to the customer can vary from 15% up to 40%. The wood will shrink in service when
erected, as beams or as decking. A 100mm decking piece can shrink up to 8mm, but generally it will be less than this (2 to
3%). As the timber is essentially air dried in uncontrolled conditions, it should only be used for suitable applications where
shrinkage can be tolerated, such as structural usage, or decking. Do not use it for tongue and groove flooring, or fine
furniture, for instance, unless dried.

Designing structures with Balau
The strength of Balau is 2.5 times that of pine. (Modulus of Elasticity is 21000 N/mm2 compared to pine of about 7800).
Try to break a piece of Balau and a similar cross section of pine and see the difference!
Balau is stronger and stiffer than pine and this fact must be drawn to the attention of the designer to take advantage of
this.

When choosing deck joists, 40mm beams are recommended over 30mm beams for better screwing capacity - the wider
40mm size gives better holding power.

Structural Balau can be obtained in very long lengths, e.g. 8 metres, but this must be pre ordered months in advance as
the harvesting and shipping procedures all have to be arranged. As the shipping method is containers, lengths are usually
below 6 metres.

Balau is one of the very few tropical hardwoods that can be used for structural applications, and that is available in the
required lengths.




 Updated 25. March 2009 - If you feel more information is required on this document please let us know at sales@somtim.co.za   Page 1 of 2
                                                            Balau decking
Decking profile
Decking is machined from air dried balau. It is generally reeded (fine grooves) on 1 face. This provides stress relief and
better recovery during production. It is often incorrectly seen as an anti slip groove, however it can be used upside down
on staircases where anti slip is required.
If laid with the grooves on top, sanding and oiling is more difficult, water collects in the grooves, and screws are difficult to
hide and countersink neatly.
We recommend that balau decking should be laid smooth face upwards.

Installation
Due to balau being a natural product, and usually installed in adverse conditions (i.e. direct sunlight), some movement of
the timber can be expected.
It is recommended that balau decking be installed on similar density timber (e.g. balau) bearers with stainless steel
screws. If this is not possible or uneconomical a more cost effective bearers (e.g. pine) can be used. Care should be
taken that screws are long enough to hold.
Bearer spacing for 19mm is 450-500mm and plank spacing of 4mm is recommended.

Screws
Somerset Timbers stocks good quality Stainless Steel screws with a self tapping fine thread, 4.8mm shaft and a Posi
Drive head. A 4mm or 4.5mm drill bit is recommended for pre drilling. A 60mm length is recommended but 50mm can be
used as well.
A specialist countersinking bit is recommended - it is difficult to countersink correctly with an ordinary drill bit.
Galvanised steel posi screws are NOT recommended due to their relatively short life span.
It is not worth the trouble of using cheap screws (e.g. ordinary chipboard screw - stainless or galvanised) on an expensive
product such as Balau.

Care
After installation, Somerset Timbers Galseal should be applied to feed oil back into the timber. Various colours are
available. This can be reapplied as necessary - a 2nd coat probably after 6 months and then yearly.
Alternatively Boiled linseed oil thinned with turpentine can also be used.
The use of surface sealers and varnishes is not recommended as this causes the timber to heat up excessively in hot
conditions and does not allow the timber to breathe.
If no oil is applied, balau will weather to a grey colour. The debate on whether an oil must or must not use is a long one !
Due to the density fine hair cracks are a characteristic of the timber as it dries over time.

After a good installation and periodic maintenance, balau should provide a very long lasting, beautiful surface.

Balau Properties
Planing                      Difficult                                   Planing finish                 Smooth
Boring                       Slightly difficult                          Boring finish                  Smooth
Turning                      Easy                                        Turning finish                 Smooth
Treatability                 Very difficult                              Nailing                        Very poor - must be pre drilled
Air dried density            850 to 1155 kg per cube                     Compression strength           Perpindicular: 9.79 N / mm2
                                                                                                        Parallel: 76 N / mm2
Static bending               MOE: 20100 N / mm2                          Shrinkage                      Radial: 1.7-2.1%        Tangential 3.5-
                             MOR: 142 N / mm2                                                           3.9%
Botanical name               Shorea spp.                                 Shear strength                 15 N / mm2



  Updated 25. March 2009 - If you feel more information is required on this document please let us know at sales@somtim.co.za     Page 2 of 2

								
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