Timber Tales: Choosing the Right Wood for Your Project | Wood Durability Insights

Foreword by Ian Thompson, Editor

Welcome to our latest video, where we delve into the world of timber and its use in various building projects. If you’re someone who enjoys designing and constructing with timber, you’re probably aware of its numerous benefits. Not only is it sustainable and helps combat climate change, but it also provides a sense of wellbeing with its biophilic effects.

Yet, when it comes to choosing the right timber, questions about its durability and fitness for purpose often arise. In this video, we aim to address these concerns and guide you through the process of selecting the ideal timber for your specific needs.

We will explore various aspects of timber, including its nature, decay process, durability, and the different factors affecting its lifespan. This video will also help shed light on the importance of treating timber to enhance its resistance to environmental factors and pests, if they are a problem in your country, thereby extending its service life.

The video includes insights from the National Center for Timber Durability and Design and the Timber Preservers Association of Australia, providing a comprehensive understanding of timber treatment methods and standards for construction.

So whether you’re a seasoned professional or a DIY enthusiast, join your hosts WoodSolutions Australia as they demystify the world of timber, helping you make an informed decision for your next building project.

Timber Tales: Choosing the Right Wood for Your Project | Wood Durability Insights

Video Transcript

We all love designing and building with timber whether it’s for domestic, commercial or landscaping purposes. We also know the good news stories about wood – it’s sustainable, it helps tackle climate change, it even makes us feel good with its biophilic effects.

But when you choose or specify to use wood, the question of durability arises. Just how long is the service life of the timber you’re using? Is it fit for purpose? Let’s look at some of the factors behind choosing the appropriate timber for the right job.

Wood by its very nature decays. Some species of timber decay faster than others, while the environment in which it’s being used for is also a factor. There’s moisture and fungus and of course hungry termites to worry about. But all this shouldn’t put us off when choosing timber as a material to build with. It’s just about choosing the timber that’s fit for purpose.

We have some amazingly durable timbers, but we also have a lot of timbers that require protection, otherwise they’ll be attacked by fungi and insects. And if you put them in marine environments by marine borers, and so it’s important that we treat these timbers to kind of extend their life because that makes them more environmentally sound in terms of using timber.

The testing takes place at the National Center for Timber Durability and Design, established and partly funded by Forest and Wood Products Australia. Its aim is to identify and manage the factors that degrade wood and wood products when in use. Humans have been trying to protect timber for centuries.

And if they used to, like the Phoenicians used to smear things on the on the boats to keep them out lasting longer, people dip things and were used all kinds of chemicals unsuccessfully. And it was until about the 1830s that people actually started to figure out how to how to protect wood. And the first thing they made was creosote. And they actually then took that and figured out a way to get it in the wood.

And that was all done for the British Navy. And we still use creosote today because it’s a it’s a highly effective preservative. And our processes aren’t that different from what we use what people used in the 1830s. They’ve just become more controlled and and they’re really important in terms of extending the service life of timber.

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This is one of the many methods used – it’s in-ground field trials intentionally located in the ultra severe environments to accelerate timber breakdown and test new treatments. These have been out for about two and a half years. And you pick up the timber and you just you poke at it.

And so these are examples, you can see there’s quite a lot of decay here. And so I would take the material with my little pointy stick and I would poke around. And I would estimate the percentage of area that’s damaged by the by the decay fungus. And I can do this for all these timbers.

It’s at a timber treatment plant such as this, where untreated wood comes in, goes through its various treatment processes, and leaves ready to tackle anything nature can throw at it. We have pretty boring base of local producers, wholesalers, importers, landscape timbers as well as structural timber products. It’s really diverse. So hence over time we’ve gone from one treatment plant to four plants. And we’re offering I think about eight different hazard classes and types of treatment.

A pack of timber is rectangular or or square. And the advantage of using a square vessel is that you don’t use as much liquid whereas if you’ve got a round vessel then you’d have to have a lot more liquid to fill the void space in there. The processes of various combinations of vacuum and pressure. It’s targeted to the product that you’re being used in Australia. Timber is treated to six different hazard classes. These range from using timber in dry indoor conditions right through to the marine environments.

The Timber Preservers Association of Australia represents the country’s preserving industry and says it’s easy to choose the timber you need by interpreting a set of numbers branded on each product. The information that you need to decide the right product for the right job is actually pretty easy to find. Jack, it’s actually written on all the products um tell us about this brand.

Okay uh this is on our technical note number one on the website. The 4a8 tells me the treatment plant. The 75 tells me the active ingredient that it’s been treated with and the h2f tells me it’s protected against termites and is for framing south, that means south of the Tropic of Capricorn. Now the 75 there are 11 active ingredients currently approved for use in Australia.  Yeah and they’re expensive to analyze for everyone.  

So that’s why that tells me what to analyze for.  Okay so we know so that tells us what’s in it, that tells us where it’s from and that tells us what you can use it for.  It’s all pretty simple in terms of method.  The idea of wood preservation is to get the preservative into the wood.  So you’ve got a basically very broadly two techniques.

You’ve got you’ve either get full of vacuum on the wood and then flood it with preservative and the preservative gets sucked into the wood or you heat the wood and the heating drives the air from the wood and then when you cool it down, it sucks the preservative in. There are different solvents. There are water-based preservatives and there are organic solvent-based preservatives, and each different carrier, each different solvent, determines the method used to do the treatment.

Trader Timber is perfectly safe to touch as part of the construction process because the active ingredients have been fixed into the wood. I’m a chemist by training and so as far as I’m concerned, there’s no such thing as a bad chemical; it’s all about dose. Now, you want to stop fungi or rot and you want to stop termites and and other insects, so you’re going to have to kill them, all right? So we’re using low levels of insecticide, low levels of fungicide to stop them from eating the wood.

That the buying public or that specifiers must rely on the fact that there is oversight of this product. They, it would not be approved if it was dangerous. It would not be approved and the currently approved chemicals are under review all the time. And it’s not just Australian Timber that comes to places like this to get treated. This is LVL from Finland awaiting its turn to be treated for Australia’s harsh conditions.

There’s a set of Australian standards which ensure the chemicals being used are safe once the wood is treated. And although the industry is well established and good at what it does, more research is always being done to see if there’s a better way. So what we’re doing here is I’m going to spray the wood with an indicator which tells us where the chemical is in the wood and this is called Chrome azerol. It reacts with copper and in CCA, we have copper, Chrome and arsenic. So if the chemical is there, it’ll turn blue.

And we have two pieces of timber here, one that’s very well treated. It turned entirely blue across the cross section. The other one turned blue except at the center which is where the Heartwood is and the Heartwood is very difficult to treat and so in this case, we can see where it didn’t really react very well.

This is part of the Quality Control process with Timber. We take samples, we cut them up and we spray them to see if the chemical is is across the cross section and then we can take that piece and cut out pieces to assay it chemically so we can make sure that the chemical is where we want it at the right level for the particular hazard class we’re using.

For more about which Timber is right for your job, visit the Timber Preservers Association of Australia’s website. There, you will find easy to understand factsheets and information.

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