Timber recommendations for a project in Indonesia

Submitted by sogreene on Tue, 08/05/2012 - 13:42

Do you know what timber past projects have used to make window frames and doors? I am currently struggling to find a softwood that is commonly used on the island.

Submitted by Pilgrim (not verified) on Sat, 12/05/2012 - 12:24


If you only need a small amount of timber and/or are not too concerned about your sustainability credentials you could simply ask the locals what local timbers they use and find durable. They will normally be very knowledgeable.

But if you want to become familiar with Indonesian timber , here’s a few things I learned whilst building houses in Aceh after the tsunami:

The great majority of naturally occurring timber in Indonesia is hardwood. You specifically ask for softwood, but there is no reason I can think of that you should be specifying softwood.

For significant projects with international funders/donors, sustainability is going to be an issue. There are sustainable timber suppliers in Indonesia, but they are vey rare and going to be exporting their product to Europe etc. You’re unlikely to get their product. Furthermore if you ship unprocessed timber across regions in Indonesia you come up against a whole raft of legislation, licensing and local practices which substantially increases costs (if you are lucky) or deny you the product altogether if you are not.

Then there are legal timber sources. They are not sustainable by most criteria, as the logging companies are clear-felling to plant oil palm. But it is legal.

Then there is the other stuff. Which is a large proportion. The worst of it is logged illegally and sawn up on the spot: watch for chain saw marking on the planks. But most of it is sawn in sawmills somewhere in the forest.

I did understand that (in Aceh at least) villages had some “forest rights” that allowed them to take timber for use in the village. We were building on too big a scale to take advantage of this, but for small scale projects ensuring that new seedlings are planted to replace the trees logged might be adequate.

Indonesian timbers do have a basic grading system, produced by Ministry of Forestry which grades them for durability and structural strength. If you are going to get serious you will need that document. I may have a copy or a reference if you need it.

But next we hit the problem of species identification. The Grading System will identify the scientific and a common name for each species but out in the real world many timbers are known by completely different names (some of them potentially illuminating such as “iron wood” or “stone wood” but others less so such as “yellow wood”). Ministry of Forestry have prepared about a dozen books with such titles as Medium Hardwoods of Sumatra which would help an experienced tree guy to identify trees growing in the forest. But identifying them in the woodyard when they’re reduced to planks is a whole order of magnitude more difficult.

One useful book is The Timbers of Sabah which has many common names for trees throughout South East Asia, and much more information on durability, capability of treatment and ease of sawing etc.
If you are in the more developed parts of Indonesia the woodyard will most likely offer meranti. There are about 140 species which answer to this name and it is not very durable.

Once you’ve selected your species you need to get the quality right.

Traditionally, hardwoods would be cured in a log pond for a couple of years and then dried, either air-dried or kiln-dried. These days they are immediately air dried and sawn. So more warping and cracking. Only a few companies will kiln dry to a controlled moisture content.

Most tropical hardwoods are too dense in the grain to take much treatment. You might get a few millimetres penetration by soaking for a while, depending on the chemical you use, but they’re not like the most porous timbers like New Zealand pine which will achieve 100% penetration. When I spoke with the timber export department of Ministry of Forestry they talked of a government owned wood treatment facility somewhere outside Jakarta. But I was never able to find anyone who knew where it was.

So you rely on naturally resistant timber: the highest risk is to termite attack; timber with low starch content is least liked by Indonesian termites; also do not use timber in places where the timber can stay damp, which is fertile ground for termites. The people who know most about Indonesian timber are at the Agricultural University in Bogor. We also had timber attacked by lyctus beetle; this seems fairly rare, but I did hear of an attack in a development in Jakarta. The conclusion in our case was that the beetle was in the timber when it arrived; another disbenefit to air-dried timber of course.
Check moisture content in the woodyard. You will be looking in broad terms for <15%. Ace Hardware make a cheap instrument, so you can get a proper commercial one for a couple of hundred dollars. I wrote a Spec identifying acceptable moisture levels at each stage of the process which we adopted for our supplies.

If you do not want to use natural forest hardwoods you have some other options, maybe:
For doors we used albasyah core which is a really cheap and nasty timber plantation grown for the paper industry. But it soaks up treatment wonderful (pressure treated for three hours). The supplier also used durian timber (orchard timber from old trees), again treated. The timber was then cut into small pieces and glued with finger joints. The whole was then veneered with meranti. Normally exported, these high quality doors were used for 2000 of our houses.

For windows we gave up on timber altogether and used aluminium, as did some of the other larger projects.

Two other projects that might be of interest if you are building a lot of houses:
One NGO imported treated NZ timber. Because it achieves 100% penetration it could be cut after import and the intention was to make the doors and windows out of the imported timber. But the fabricators in Indonesia, used to using meranti, did not like all the knots in the NZ timber and refused to process it.

One NGO built houses using steel frames and timber imported from Europe, again a pine and fully treated.