Ask An Expert

Home » Expert Advice » Ask An Expert

I am currently researching whether Laminated timber (specifically laminated timber posts being Kwilla GL13) can be used in a Bushfire prone areas, I can not find any test results or product information that the laminated timber posts will be able to with stand a bushfire attack. Any information would be useful I have read your Wood Solutions 04 but it does not mention laminated timber a also read wood solutions no 16 and this does not mention bushfire use. 

Read Answer +

Kwila is one of the species recognised in the Australian Standard as a 'bushfire-resisting timber', so the question is whether it retains its bushfire-resistant status when it is glue laminated. We are not aware of any Australian fire tests on laminated kwila posts, but there is plenty of anecdotal evidence that laminated timber performs in much the same way as 'solid' timber, eg. here: One point noted by the American Institute of Timber Construction (AITC) is that glulam beams are sometimes made with lower strength inner laminates. This means that if the outer laminates burn away the lower-strength inner laminates may not have sufficient strength to continue their loadbearing role. Glulam beams required to have a specific fire rating may need to be designed accordingly. This might not apply to kwila posts, but you could inquire from your supplier as to whether a lower grade of kwila is used in the core. The glue bond itself remains intact on exposure to fire. 

If allowed to grey off would Kwila be similar to Blackbutt if also allowed to grey off? 

Read Answer +

Yes, all timbers eventually achieve a similar grey colour but only where they are exposed – areas high up under a verandah overhang will retain their natural colour much longer or maybe permanently. So you might think about a driftwood grey wood stain if you think it might bleach unevenly.

We were looking at cladding the outside of our sun exposed verandah in Blackbutt. It seems well suited but expensive. We are considering Silvertop Ash. It would be vertical shiplap in a beach suburb and not be in contact with the ground. Is this suitable?

Read Answer +

Silvertop ash is rated Durability Class 2 outdoors above-ground, but this assumes full weather exposure. If the cladding is protected from the weather by a verandah so it never, or rarely, gets wet and is installed clear of the ground so it is out of reach of termites, then any timber can be used. Sun exposure will not cause the timber to deteriorate, but will bleach exposed areas if left uncoated. Points to watch are that the timber is kiln-dried and that its appearance meets your expectations – silvertop ash commonly contains gum veins.

What are the standard hardwood timber sizes?

Read Answer +

Sizes may vary a little from one producer to another, but the Boral size range would be fairly typical. You can access their flyer here. Note that the seasoned (kiln dried) range is the same as the range of structural pine sizes, ie. 90 x 35, 140 x 45 etc. The corresponding sizes in unseasoned ('green') timber would be 100 x 38, 150 x 50 etc, less a sawing tolerance of 3mm. Unseasoned sizes are generally a soft metric conversion of the old imperial sizes, on the basis that 25mm is approximately 1 inch, ie. 100 x 50 = a '4 by 2'.

I am wondering whether you know where I could buy some Blue Spruce timber? My elderly father wants to build a commemorative box for one of his sons who passed away a couple of years back. The Bluce Spruce was my brothers favourite tree. We are located in Victoria.

Read Answer +

Unfortunately blue spruce is not a commercial timber and you won't find it at your local timber merchant. It's possible that a woodworking group could help since they sometimes source timber from gardens, street trees etc. There are several groups around Australia and in Victoria you could try Waverley Woodworkers. They have a website here.

Can jarrah be used as a cutting board?

Read Answer +

Jarrah is quite safe to use as a cutting board. Generally when some timbers are described as 'hazardous', the term refers to the inhalation of fine sawdust and/or contact with the sap or foliage of freshly cut ('green') timber. Some timbers can taint food that is left in contact for prolonged periods by imparting a flavour to the food, but kiln-dried jarrah is unlikely to do this.

I have a client in Japan who is interested in importing wood/timber from Australia. I have their specific list. Is there any protocol for this process?

Read Answer +

There are no specific legal or regulatory hurdles from this end as far as we are aware. Any quarantine or trade regulations will be imposed by the importing country (Japan in this case) rather than the exporting country (Australia). If the timber in question is for structural use then it will have to meet Japanese quality Standards which may or may not correspond to Australian Standards. Your client should be able to look into Japanese authorities' requirements.

What is Paulownia (powton tree) used for?

Read Answer +

In the mid 1990s there was considerable interest in Paulownia, with plantations established in Queensland and other States. The attraction was its fast growth, but the wood produced is of very low strength and density. On the positive side the wood reportedly has little growth stress and is very dimensionally stable, with low shrinkage during drying. In Asian countries where Paulownia originates it is used largely for furniture, musical instruments and joinery. On the negative side it has low durability and does not readily accept preservative treatment, and consequently is not suited to outdoor use. Also its softness means it is easily damaged and its low strength means that large sizes would be needed for structural applications. So while Paulownia plantations received strong promotion in the 90s we doubt that any significant quantities of timber found their way to market.

We are going to have our retaining walls done in 75 mm treated pine cladded with 90 mm merbau as suggested by our landscaper. I am trying to envision this. I know what merbau looks like but just wanting to know what this combination will look like together? And it will be capped. Do you have any example pictures or where can I find some example pictures?

Read Answer +

It was a bit hard to picture which part of the wall will be treated pine and which part will be merbau. If you write ‘treated pine images’ and ‘merbau images’ in your browser you will see what the two timbers look like. Treated pine has a greenish tinge, while merbau is reddish-brown. But be aware that unless you keep the timber oiled, both will eventually bleach to a driftwood grey colour.

I own an antique table which is made from Tasmanian timber. Would you be able to identify the timber please? I would need to send many pics of the underside so would need an email address. I would be very grateful if you would do this for me.

Read Answer +

It’s often difficult to tell from a photo, but we can have a go if you would like to send some images. It’s easier when actually looking at the timber. Perhaps the University of Tasmania’s Centre for Sustainable Architecture with Wood could give a more definitive answer if it’s possible for you to take the table to them.


Hi, I'm a student at Swinburne University of Technology and I am undertaking a Final Year Research Project on the application of Cross Laminated Timber (CLT) in the Australian Construction industry. I was hoping to get the contact details of someone who may be an expert in the emergence of new building materials into the market specifically engineered timber products such as CLT if possible. I would like to ask them a few questions in regards to the potential application of CLT as well as the potential barriers the new material may face in coming to Australia and if there is any action being taken currently to overcome these barriers. I would also like to touch on the perception and willingness of the Australian construction industry to take on innovative materials/practices. Regards, Chris.

Read Answer +

An end-of-year review of our work has shown that we overlooked your question back in October. Sincere apologies for this oversight. It might now be too late to help with your final year research project but perhaps you found the information you needed on the net. There is a good general article on CLT in Architecture & Design: click on this link. As you are probably aware, the world's tallest CLT building is the Forte building in Melbourne, so we can't say that the Australian construction industry is unwilling to try new practices, although it's true that most new multi-storey buildings are constructed with more familiar materials. You might also be interested to see our Technical Design Guide on Cross-Laminated Timber.

Why is plywood so expensive in Australia compared to North America, especially in light of the fact that other engineered wood materials such as chip board, melamine, and MDF are much closer in cost?

Read Answer +

We haven’t carried out any studies of comparative prices and if plywood is significantly cheaper in North America we can only suggest that it’s because of economies of scale. The North American market is much larger than the Australian market and it’s likely that all wood products are cheaper there. Perhaps the Engineered Wood Products Association of Australasia (EWPAA), formerly the Plywood Association of Australasia, could give you a more informed answer. You will find contact details on their website at


What is the slenderness ratio for MGP 10?

Read Answer +

We weren’t sure if your query related to a beam or a column. The slenderness of a column (compression load) is calculated by dividing the effective length by the cross-sectional dimension. Minor axis buckling occurs when the column buckles around the lesser dimension. For example, a section that is 90 x 35 will bend more easily around the 35mm dimension and that is called minor axis buckling. Bending around the 90mm dimension is called major axis buckling. The effective length of the column or other vertical member is the distance between restraints. In the case of a 2.4m stud with nogging at the mid-point, the effective length would be 1.2m.

We need 25 mm ply wood to be used as pallet for manufacturing of fly ash bricks, the load of the hydraulic press we use is 400MT capacity. We press the semi wet mixture of flyash, sand and gypsum to form a block of size 9"X4"X3" on the wooden pallet. Size 970mmX910mmX25mm plywood. Please suggest which type of plywood we can use. The plywood will be used 8 times a day, and it should last min for 3 to 4 years.

Read Answer +

Our service gives general advice rather than structural design, and in this case we weren’t sure whether the plywood was spanning between supports or fully supported over the entire area. But we can say that the most suitable type of plywood would be one that is designed for use in concrete formwork. Such plywoods have a surface ‘overlay’ which reduces the likelihood of moisture absorption and allows multiple uses. However, it might be a little optimistic to achieve a life of 3 to 4 years if it is used 8 times a day.

I would like more information on the correct storage of timber products on building sites, so mainly structural members and framing materials. In particular, I'd like to know what to do with timber that is delivered wet or that gets wet onsite - how should it be stored to dry it out and what should be done in terms of checking moisture content before use. Thanks.

Read Answer +

Australian Standard 1684 includes advice on the storage and handling of timber (Appendix H). It's not possible to reproduce Appendix H in full here, but the important details are (i) seasoned framing timber should be stacked 150mm clear of the ground; (ii) an impermeable covering should be secured at the sides but not wrapped under the timber; (iii) ventilation should be allowed under the stack. If the timber has got wet on site, as in your case, it would also be advisable to strip it out with spacers in between to facilitate drying and prevent mould from growing between the timbers. Of course, this depends on how long the timber is likely to be in storage before being used. If it is likely to be used in a matter of days, re-stacking it may not be warranted. Regarding checking moisture content, the best way to do this on site is to use a battery operated moisture meter, selecting pieces at random. However, if the timber is only wet on the surface it should dry quickly and structural performance is unlikely to be affected.

In the web site , we note that Merbau has been tested and found to meet the required parameters without having to be subjected to fire retardant treatment:
Could you please send me the test report / certificate ?

Read Answer +

Merbau (also known as kwila) is listed in Appendix F of Australian Standard 3959, Construction of buildings in bushfire-prone areas, as one of seven 'bushfire-resisting timbers' and therefore satisfies regulatory requirements. The original test report which justified the inclusion of these seven timbers in AS 3959 can be accessed via this link:

We are building a new house on Sth coast NSW. Can you please advise about timber choices for the decking. It is mainly undercover, we don't want it to go grey. Merbau has been suggested but I am concerned about the ethics of the harvesting of this rainforest timber.

Read Answer +

Merbau is a good choice for decking from a performance point of view. Regarding the ethics of harvesting it, Australian timber importers have been required to conduct due diligence for some twelve months now to ensure no illegally sourced timber is imported. Click on this link to read more about the Australian Government's initiatives in this area: Of course, there are also Australian-grown timbers that are suitable for decking and these include red ironbark, spotted gum, blackbutt, tallowwood, etc. As to whether the decking will go grey, that depends on how regularly you apply a decking oil or stain. All timbers will turn a driftwood grey if exposed to the weather without a coating.

I'm considering constructing some window sashes complete with glazing. Would either of these timbers be suitable, dark red meranti or jarrah? Thank you for your advice.

Read Answer +

Dark red meranti and jarrah are both suitable for window joinery, but jarrah has a higher durability rating. Dark red meranti is rated Durability Class 3, while jarrah is Durability Class 2 outdoors above ground, according to Australian Standard 5604. That is not to say that dark red meranti won't give adquate service, unless there is severe weather exposure, in which case jarrah might be the better choice. Note that if you intend to use an oil or stain finish, the glass should be installed with wooden glazing beads bedded in silicone – putty performs best when protected by a paint finish.

For more information about the design, construction and maintenance of timber windows and doors, download the free WoodSolutions guide Timber windows and doors.

window, windows, meranti, jarrah, joinery

I plan to build a house in Vic. At the moment I am considering a number of options including CLT structure. Would you please contact me to discuss this option?

Read Answer +

You might find the information you need in our Technical Design Guide #16 on CLT, available for download here. If not, and you wish to discuss options with an adviser, we have a special phone line available on 1300 414 004 available Mon - Fri 9am – 5pm. Charges apply.

CLT, housing, house, cross laminated timber

Displaying 20/99

Show me 10 /20 /30

Haven't found what you're looking for?

If you have not found the answer for your question for in the Search results, please call the Expert Advice line or send us an email for a prompt response.



Call the WoodSolutions Expert Advice line on 1300 414 044*
Available Mon - Fri: 9am - 5pm

*Please note, there is a charge, determined by your telecommunications provider, for these calls.
This service is not available to international callers.

Are you looking for a supplier?