Ask an Expert

Ask an Expert

The environment, sustainability & recycling

Like to know what wood to use building a pergola or framing a barn? How about the difference between tung oil and polyurethane as a floor finish? How to revive decking or deal with merbau stains? Or how to meet the building code or bushfire standards? Or ask about the environmental advantages of wood or forest certification?

Q. Thanks for getting back to me with regard to the timber used in the wagon. That’s really interesting re the red Baltic pine and red deal. Do you know where I can find some? New or recovered timber would be fine.

Baltic pine flooring is still available in the marketplace, for example Wright Forest Products have what they call Nordic Redwood in a size of 160 x 22. For more information click on this link: Alternatively companies that specialise in recycled timber can supply reclaimed Baltic pine flooring, eg. Timber Revival, Urban Salvage, etc. You may find more suppliers on the net.

Q. I plan to replace 4 posts and the timber beams above which support a patio roof 2 metres wide and 9.5 metres long on a house on the beach. I would like to use spotted gum posts ( 150mm square ) and iron bark beams (250mm by 70 mm) that I have saved and would like to live again. This is all seasoned wood over 40 years old which is not treated like modern day wood. What would you advise??

We feel it's an excellent plan. Your recycled timber will be well seasoned and therefore will not shrink or crack in service. Spotted gum is rated Durability Class 2 in ground contact, but perhaps you plan to support the posts out of the ground in which case spotted gum is Durability Class 1. Ironbark is Durability Class 1 in ground and out of ground. The seaside environment is not particularly hazardous for hardwoods but all fasteners will need to be stainless steel if the house is by the beach.

Q. 1.Which advanced forestry systems can be used to avoid deforestation? 2.From which resource is CLT, LVL and LSL types of engineered wood are manufactured?

1. Timber from tropical forests often passes through many hands before it reaches the market, so tracking systems are used to ensure its legality and sustainability. Tracking systems trace the timber back to the forest from which it came. Tracking can be by documentation using "chain of custody" protocols, or more recently by DNA fingerprinting. DNA fingerprinting uses the genetic data inherent in wood as a natural barcode to track it back through the supply chain. You will find more information about these systems on the net, for example by entering "DNA tracking of timber" in your browser. Timber produced in Australia for local use is easier to monitor since its source is known and production is controlled by government regulation. 2. Cross Laminated Timber (CLT) utilises the softwoods spruce and fir. Manufacturers are located mainly in Austria, Germany and Scandinavia. LVL manufactured in Australia generally uses plantation-grown softwood, although a hardwood product is also marketed. Some Laminated Strand Lumber (LSL) is made from hardwood and some from softwood, generally using small-diameter logs and thinnings that are not suitable for sawn timber production. As with other engineered wood products, you will find more detailed information on the net.

Q. Recently we demolished our home but saved the oregon timber beams which are approx 5m in length and 8" X 2" and I was wondering if you knew of anywhere that I could get these planed in Sydney so as to make a dining table out of them. Bye for now Kathy Harris 0297723291

Joinery shops and timber merchants are often reluctant to plane recycled timber because of the possibility of striking nails that would damage their equipment. Your best bet would be to find a company that specialises in recycled timber, since they will be accustomed to dealing with the problem. Some have metal detectors to find hidden bits of hardware. You will be able to find recyclers in your area by searching the net.

Q. I've been organising the building of a house, and have spent many hours trying to source suitable timber. The house is BAL 29, which severely limits the species that can be used, especially for windows and external doors. My criterion is timber whose harvest hasn't done permanent damage to a natural ecosystem. My priorities are: 1. used 2. timber whose harvest I can discuss with the supplier and make up my own mind about how it has affected natural ecosystems 3. FSC certified timber. I'm willing to pay more than whatever's cheapest at the local timberyard, but am not loaded with money, so have to be cautious about price. I've managed to find some second hand timber yards that may be of help, and a couple of small local millers, and about one FSC-certified timber supplier. I heard your ad on commercial radio, implying it was easy to find suitable timber, and if this is so, I'd be grateful if you could provide me with a list of suppliers.

BAL-29 areas are regarded as high risk, so if bushfire shutters are not installed doors and windows must be made from one of the seven timbers classed as "bushfire-resisting". If bushfire shutters are installed, complying with the Australian Standard, any type of timber can be used for doors and windows. Assuming you don't plan to install bushfire shutters you should be able to find some of the bushfire-resisting timbers in recycling yards since six of the seven are native Australian species. There are many timber recycling businesses around Australia and you will be able to find their locations on the net. Regarding FSC-certified timber, you will find a list of species produced under FSC certification if you go to the Forest Stewardship Council's website at One of the FSC-certified species, spotted gum, is classed as a bushfire-resisting timber. While some Australian timber producers work according to FSC certification, others have opted to use the Australian Forestry Standard which we consider carries equal weight. You can find out more on the AFS website at For an impartial assessment of the condition of Australian forests you might be interested to see the five-yearly reports prepared by the Australian Government as part of the government's commitment to the Montreal Process. These can be downloaded via this link

Q. Can you buy recycled treated pine timber and decking in or near Melbourne?

There are several companies in and around Melbourne specialising in recycled timber, including Shiver Me Timbers, Timberzoo, etc. However, it's more commonly untreated timbers that are recycled rather than treated pine. You will find a variety of durable hardwoods, cypress pine and other suitable species in recycling yards. However, if you particularly want to source treated pine we suggest you contact one of the recycling companies directly to see whether it is available.

Q. How much carbon is stored in 10 kg piece of pine framing?

Growing trees absorb carbon dioxide from the atmosphere through photosynthesis and then store the carbon by converting it into wood. About half the dry weight of a tree, or wood product, is carbon, so 10 kg of dry pine represents about 5 kg of carbon. It takes 3.67 tonnes of carbon dioxide (CO2) to produce one tonne of carbon, so if you know the weight of a piece of wood you can work out how much carbon dioxide it has taken from the air. (For example, 2 kg of wood contains approximately 1 kg of carbon that took approximately 3.67 kg of CO2 to produce.) Carbon stored in wood is only released back to the atmosphere when the wood or wood product decays or is burnt.

Q. I have noticed on a few websites that they are saying "Recent research by the Cooperative Research Centre for Greenhouse Accounting compared the amount of greenhouse gas emissions generated by the manufacture of timber products with the amount of greenhouse gas emissions generated by the manufacture of common alternatives. The research showed that more than 25 tonnes of greenhouse gases could be saved if timber products were used instead of the common alternatives, to build a family home." and "Timber is one of the world's most environmentally friendly building products. It is natural, renewable and sustainable. Choosing wood over energy-intensive building materials such as concrete, steel, aluminium and brick can have a substantial impact on carbon emissions. Forest & Wood Products Australia (FWPA) research found 25 tonnes of carbon per Australian home could be saved by choosing wood where possible". Do you know where I could find the report on this research? I have looked everywhere and haven't been able to locate this.

The reference to a potential saving of 25 tonnes of greenhouse gases is contained in a brochure published under the auspices of the Copoerative Research Centre for Greenhouse Accounting, which can be found on the net at Refer to page 3, halfway down the right-hand side. You might also be interested to see the research report on the same subject, published by Forest & Wood Products Australia (FWPA) at

Q. I was reading about recycled wharf and bridge timbers. Do you know who sells them in NSW?

There are several businesses in NSW that specialise in recycled timber. We don't have a comprehensive list, but they include Timber With Veins Pty. Ltd. (website, the Heritage Building Centre (website, and The Recycled Building Yard (website You may be able to find more contacts on the net.

Q. Regarding the calculation of carbon sequestration rates for various tree plantation species - how can I access this information, or what are the accessibility criteria?

There is no need for trees planted for carbon sequestration to be of any particular kind. However, a useful calculator (the Carbon Sequestration Predictor) has been developed by the New South Wales government and its use is explained in their Prime Facts newsletter of January 2010. A copy of the newsletter can be downloaded from the net at, and the calculator itself can be downloaded from


Did you know?

About 16% of Australia’s 147 million hectares of native forests are in nature conservation reserves.