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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. We have constructed a Conference Centre in Marysville, country Victoria. Due to the Bushfire Attack Levels we were required to provide BAL 19 & BAL 29 timber for the windows and toughened glass generally to windows and doors. Due to the financial situation of the Client the project construction took 24 months to complete. The doors and windows were installed late 2011 and the project was completed February 2013. All the external windows and doors were coated with clear external varnish before the end of 2011. We are having extreme movement of some doors both internal and external. This movement is generally when sun hits it directly and moves each day during the day. The timber species used by Sette Windows was KDHW for BAL19 and Silver Top Ash for BAL29. We need to know of a way to arrest the movement so that doors don't stick or have too great a gap. It is also affecting the movement of the double hung windows that sometime stick and other times are free operating. I would appreciate some expert assistance to resolve the issue for the Client.

Timber only "moves" when it's changing moisture content so it seems odd that it's continuing to swell and shrink a year after completion. If the building is in a particularly wet location perhaps canopies could be installed to shield the external doors and windows from full exposure to rain. It's also important that the contractors sealed the doors and windows on all surfaces, eg. top and bottom edges of doors are often overlooked. If rain runs down the face of a door and is absorbed into the bottom edge the door will swell. Sealing top and bottom edges is also recommended for internal doors. Presumably the internal doors don't get wet, but bare wood reacts to changes in atmospheric humidity by swelling and shrinking, although to a lesser extent than outdoors.

Q. I am trying to specify a sustainable, non-toxic plywood for a product that will be locally made in Melbourne. We will obviously source FSA/PEFC timber, but my question is about the glues: Am I correct in believing that formaldehyde based glues are toxic if a ply sheet is composted in soil and as such most ply is landfilled? Based on this assumption I am trying to find a non-toxic glue that we could use to custom laminate ply. Do you know of any products which could be composted and considered non-toxic? (I am investigating casein glues, which seem to be promising...)

Your question is a little outside our field of expertise, which is wood properties rather than adhesives. We are not aware of any Australian research into the use of plywood waste in compost, but information from Canada indicates that plywood manufactured with formaldehyde adhesives can be used as part of a compost mix as long as it hasn't been painted or stained. You can read more on this website: Note that casein glues will withstand occasional soaking, but if repeatedly soaked and dried they will eventually fail.

Q. Hello & thank you, We have a brushbox floor which we have just had sanded & re-coated with a 2-pack polyurethane. We have various pieces of furniture - chairs, tables etc and was wondering what is the best stopper for the chairs etc that will protect the floor from scratching? (This has happened in the past.)

It's certainly a good idea to fit protective tips on chair legs, particularly if the chairs have a metal frame. We haven't researched this in detail but we are aware that the Clark Rubber Co markets a range of chair tips and buffers. You can view these products on their website at

Q. I am interested in Australian hardwood veneers that I can use to make coasters and place-mats which I will apply a cork backing to, and polyurethane a coating over the prints. Could you please help me with who can supply the relevant veneers which I could then cut to size? They are for a series of 'Australiana' products with my own photos I'd like to manufacture on timber mats.

If you go to the Timber Veneer Association of Australia's website at and click on the tab that says "How to Find Us" you will see contact details for the major veneer suppliers. Many of them supply sample packs of veneer which might be enough for your purposes, or if you need a larger quantity one of the listed companies in your area should be able to help.

Q. I saw a repeat story on ABC TV's Landline program today which was titled Hign Tech Timber. The story had an interview with the CEO of the AFPA Mr Ross Hampton who referred to developments in wood fibre nanotechnology that has potential in replacing plastics for various applications. I would be interested to learn more about such initiatives and would appreciate any information and reference sources that may be available. The reason for my enquiry is that I am an architect undertaking post graduate studies at Harvard Uni Graduate School of Design and I would be interested in undertaking a research project investigating commercial applications for such new technology and particularly scope to team this with emerging 3D printing / additive manufacturing. Kind Regard, Peter Burke 0425 707 508

Discussion in Australia about wood fibre nanotechnology is more in the nature of something our forest industry should look to in the future, rather than something that is actually happening now. For example, the Australian Forest Products Association (AFPA) is proposing that Australia should establish a National Institute for Forest Products Innovation to encourage developments such as wood fibre nanotechnology. You can read more via this link: Meanwhile the US and Canada seem to be leading the way. You will find various reports on the net if you write "wood fibre nanotechnology" in your browser.

Q. I am enquiring if someone can call me in regard to a query if you can create an effect on timber which I want to achieve. I have an image that I can send through. It is for a roll out retail store and it will be required at numerous stores.

We don't produce timber ourselves - our website simply provides an advisory service. It would be best to discuss your requirements with a specialist joinery shop in your area. However, if you would like to forward an image to the same address as your original query we will see whether we can point you in the right direction.

Q. Do you provide consultancy, audit to timber used as exterior windows and doors? To check why it warps or twists, poor detail? Please advise.

We don't have staff to carry out site inspections, but there are various organisations in different States that could help. If you write Association, Society or Institute of Building Consultants in your browser you will find some useful contacts. If you feel the wrong type of timber has been used for your windows and doors, we could comment further if you provide some more details, eg. type of timber and a description of exactly what has happened. However, it's probably better for someone to view the problem first-hand.

Q. I am seeking advice on timber construction detailing, particularly its secure engagement with steel. We are documenting 75 cabins to be erected in Byron Bay, constructed from prefabricated steel frames with timber infill detailing.

We weren't sure whether the "timber infill" was internal or external. There are no special requirements for timber to steel in a stable indoor environment, but outdoors can be more problematic. Timber and steel have quite different movement characteristics  in response to changes in the weather. For example during prolonged cold wet weather steel will contract while timber will absorb moisture and swell. The opposite occurs during hot dry spells - steel expands and wood shrinks. This can put stress on fasteners and slight movement in opposite directions may need to be allowed for. Another issue arises if the timber is treated with copper-based preservatives. If exposed to rain, traces of copper can leach out and cause galvanic corrosion due to dissimilar metals coming into contact. However, this is not a problem with kiln-dried wood in a dry environment.

Q. I am interested in specialising in timber engineering. I have a Certificate in Building from TAFE and have worked in timber construction in Australia and France for the past 25 years. I would appreciate any information or guidance that you can provide.

If you are contemplating further study, there are a couple of possibilities - the University of Tasmania runs a Graduate Certificate in Timber which might be suitable. You can find out more via this link: If you are looking for courses more specifically focussed on engineering design, the University of Tasmania can also help. Just write "timber engineering design courses" in your browser. If you are wanting to start building timber structures in Australia, based on the experience you already have, it could be worthwhile to contact the companies that market engineered wood products such as LVL, CLT, etc., or perhaps circulate your CV to consulting engineers who have a track record in designing timber structures.

Q. I live on the Sunshine Coast (Qld) and we recently had some trees chopped down and thought we would use the timber for our slow combustion fireplace. The trees are Black Wattle. We were advised that this timber is one of the best for our fireplace, but we were advised by someone different that Qld Black Wattle is no good at all and burns very quickly. Just wondering who is right. Can you help please?

Any wood can be used for firewood - in fact the heat output from all species is very similar per kg of wood. A kg of pine gives out about the same heat as a kg of red gum, but it takes up a lot more space. Or to put it another way you would have to stoke the fire more often if your pine logs were the same size as your red gum logs. So when people talk about a "good" firewood they mean one that is reasonably dense, burns steadily without leaving a lot of ash, and produces hot coals. The density of black wattle varies considerably and some of it can be quite light, not much heavier than pine. The lighter material would certainly burn more quickly than a heavier hardwood and would not tend to form coals. However, there's nothing to lose by giving it a try. Just make sure you allow time for it to dry. Wet wood gives off less heat than dry wood.


Did you know?

Logs from plantations cannot produce the sawn hardwood timber produced from logs currently harvested from native forests.