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Hi, im in a BAL40 zone. I want to build a veranda, and am unable to work out if I am able to use timber or not in the construction. I want to use Blackbutt or Ironbark posts and beams, which will be exposed timber. I will then use f17 vicash for the rafters and battens, plus cover the veranda with metal sheet roofing. Does the standards allow me to use these timbers?

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Bushfire regulations look to the roof elements of verandahs and similar attached structures. In a BAL-40 zone if the verandah is separated from the roof space of the main structure by a bushfire-compliant wall that extends to the underside of a non-combustible roof covering, you just need to line the underside of the rafters with 6mm fibre-cement sheeting. The regulations outlined in the Australian Standard make no direct reference to supporting posts, but we recommend the use of bushfire-resisting timber. Blackbutt or ironbark would therefore be fine since both are classed as 'bushfire-resisting'. 

By comparing with the suppliers products lists and SA HB 1.8-2013 appendix A, I found that glulam and LVL cross section size could be different. Under this circumstance, if there are any rules to make standard sizes. Furthermore, when we design timber structures by using these two materials, do we need to decided which supplier will be choose firstly, then started design process, or we can design the structure first, then ask the supplier to provided the material size which we decided to use? Thanks.

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LVL dimensions and properties are not standardised. For example, Tilling's SmartLVL comes in thickesses of 35mm, 42mm and 58mm, whereas Carter Holt Harvey produces thicknesses of 35mm, 45mm and 63mm. Both produce a limited range of 75mm material. They also have different characteristic strength properties, so yes, when designing in LVL it is necessary to select a product at the start of the design process and nominate that product in the specification and on working drawings. However, Australian-produced glulam is made with a standardised range of properties and you will find more information on the net here: http://www.lamtim.com.au/gltaa.pdf

Could you please advise the best type of glue for assembling furniture made from American Oak. With Thanks. David Mee

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PVA is the standard woodworking glue which achieves a bond as strong as most woods, ie. if the joint breaks there is 'wood failure' (bits of wood come away and remain stuck to each component). However, PVA needs a closely fitted joint without significant gaps and with a reasonable surface area coated with glue. Also don't rely on bonding to end-grain because the glue will be sucked into the wood. We assume your furniture will be in a dry location, ie. the glue doesn't need to be water-resistant. If water-resistance is required then specially formulated PVA's are available. We suggest you check the websites of manufacturers such as Selleys, Titebond etc. for further details. 

I'm designing for the first time a timber framed complex of townhouses and I have a program related query. Is there a specific program that already includes/satisfies the AS in regards to timber framing, or is any "timber framing extension" of the common programs (I personally use REVIT) suitable? Thanks for the clarification

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There are several software programs that give you span tables and the ability to design components but perhaps won't generate the complete solution you are looking for. As far as we are aware there are none that integrate with REVIT. However, you might find Smart Frame software helpful, as well as other programs available here

This is a test question - please supply a test answer

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Test answer 

test - Peter could you please answer this so we can check the auto-reply generator? I'll delete it later. Thanks David

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Answering test message

Hey,
Just a quick question. I'm a hobby builder and I'm interested in making some chopping boards. I really like Australian cypress I've used it before to make a table top. Was just wondering if anyone knows of any reason this would not be suitable to use for chopping boards?

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Not sure cypress is the best choice for chopping boards. A good quality is its dimensional stability, but when freshly machined it has a slight camphor-like smell that could taint the food. If you have used cypress before perhaps you have noticed it. No doubt the smell and possible taint go away after a while, but more "bland" woods include hoop pine, kauri pine, and in the hardwoods, Victorian ash. 

We are interested in using vertical shipplapped Silvertop Ash on a curved wall and reception desk. The radius of the curve is 14 feet, the height is 12 feet, and the length of the arc is 16 feet. Do you have drawing details that shows how to accomplish this? What is the best product for this? What is the maximum height of each piece of wood plank? Can this product be shipped to the U.S. or is there another U.S. distributor? Thank you.

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We don't have any architectural drawings that show shiplapped boards on a curved wall, but if you click on this link you will find an archive of images of curved timber walls: http://woodformarch.com/blog/10-gorgeous-curved-walls-architecture. It's not practical to curve the boards themselves but they can generally be fitted to a gentle curve - a bit like building a curved brick wall using straight bricks. It might be a good idea to talk it over with a skilled carpenter to work out the practicalities. We are not aware of any US distributors of Australian silvertop ash but it might be possible to arrange for a supplier to export a shipment to the US. You will find companies that deal in silvertop ash by searching the net, eg. here: http://www.brittontimbers.com.au/timber/silvertop-ash

I want to know how do you connect one I-beam to another?

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We weren't sure whether you want to connect I-beams at right-angles or end-to-end. It's not recommended by manufacturers to join I-beams end-to-end and not usually necessary given that they are available in lengths up to 13m. However, it is sometimes necessary to connect them at right-angles and a typical detail is provided in the Hyjoist installation guide. Note that other manufacturers may have slightly different recommendations and the manufacturer's specific details should always be followed.

I am fixing zincalume corrugated iron wall cladding to termite treated pine stud wall framing (LOSP timber). Do I need to use galvanised fixings due to the treated pine? Regards Carol Carellas Architect ( Paul Campbell Architects Adelaide)

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Only timber that has been treated with copper-based preservatives (CCA, ACQ, etc) needs special consideration on account of an enhanced corrosion effect, and then only in the presence of moisture. That is because exposure to rain (for example) can leach out traces of copper that react with dissimilar metals to cause galvanic corrosion. Common LOSP formulations are not corrosive and presumably the timber will remain dry in service. However, galvanised fixings may still be recommended if the wall cladding is exposed externally.

Is meranti a satisfactory timber for use in windows and glazed doors? It will be painted.

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Meranti is suitable for general joinery use because it is dimensionally stable once it is kiln dried. Meranti is divided into two groups, light red and dark red. Light red meranti, the more commonly imported type, is only rated Durability Class 4 outdoors above ground. Timbers in this group have a probable life expectancy of up to 7 years when fully exposed to the weather, according to the relevant Australian Standard. Of course if the windows and doors in question are protected from the weather, eg. by a verandah, meranti will last indefinitely. In practice light red meranti may last much longer than 7 years if kept well painted, depending on severity of exposure and local climate. However, because it is less durable than some other timbers we prefer to see light red meranti preservative treated when subjected to full weather exposure. A suitable treatment is the LOSP process. If available, dark red meranti is the more durable type, falling into Durability Class 3 outdoors above ground with a probable life expectancy of up to 15 years. Again this is likely to be exceeded if the doors and windows are kept well painted, but, as with light red meranti, the actual life of the timber will vary according to severity of exposure and local climate.

Does 12 mm Type B plywood ceiling and wall linings fixed at 600 centres warp and twist as suggested by our Builder. He is recommending veneer MDF as a better alternative.

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Plywood is a particularly stable product because of its cross-banded construction where each ply is laid up with the grain at 90° to its neighbour. We consider 12mm plywood is very unlikely to warp or twist if fixed at 600mm centres. In any case wood products only warp or twist if gaining or losing moisture and we assume your linings will be in a dry, stable environment. Veneered MDF is an acceptable alternative but no more stable in our opinion. 

We require assistance to understand the limitations, weights, and support requirements to use a hardwood timber batten as a screening element spanning close to 6m in height

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The weight of hardwood battens will vary depending on the type of timber and, of course, on their size. A large cross-section would be needed to span 6m without warping, so it might be more practical to introduce intermediate support points if possible. A suitable timber would be merbau, density approx. 850 kg/m³. We understand merbau was used successfully in the Adelaide Zoo upgrade and further details of sizes and spans may be available from the architects, Hassell.

I have a large American oak in my front yard. after I have received a permit I would like to have it removed. do you know of a firm that removes and then uses the timber? thanks

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American oak is a highly desirable timber, but it’s generally not economically viable for a timber company to harvest a single tree in the middle of suburbia. They would have to send a crane truck with at least two men, a chipper to mulch the leaves and twigs, then take the log to a sawmill which is likely to be some distance from your home. Presumably the tree is still alive so it would be sawn into ‘green’ timber which then has to be kiln dried before it can be used for joinery. The cost of these operations is likely to exceed the value of any usable timber which is produced. So your best course of action is to engage a conventional tree removal company that will either take the timber away, or cut it into short lengths for local people to collect as firewood.

Do you have any detailing experts. We have a circular cone shaped building we want to clad in timber. Do you have any details of how this can be done or someone we could consult with. Thanks, Gaetane. Our contact number is 08 8239 9000.

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We feel this is verging on being a joinery job and suggest you contact a firm familiar with complex joinery. In SA, Adelaide Heritage Joinery (website here: http://www.adelaide-heritage-joinery.com.au) or the similarly named Heritage Joinery (website here: http://www.heritagejoinery.com.au) should be able to help.

Are there any resources on the effects of fire on timber and repairs recommended?

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The effect of fire damage can be assessed according to Australian Standard 1720 Timber structures, Part 4: Fire resistance for structural adequacy of timber members.

I have a piece of new camphor laurel taken from a felled tree. What should I do to prevent cracking while it dries out? Should I paint ends? Is it best to remove the bark? How long should I leave it to dry?

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We suggest taking the bark off. Although the bark can form a natural moisture barrier and help to slow down the drying process so it occurs more evenly, sometimes mould will grow under the bark, which is undesirable. Since wood dries more quickly from the ends than the sides it’s usually sufficient to seal the ends to achieve even drying. We weren’t sure how big your piece is, but if it’s relatively small you could soak it in polyethylene glycol (PEG) to prevent splits. You will find some guidance via this link: http://www.lsuagcenter.com/nr/rdonlyres/10b3631c-0d32-42d2-8fc3-7c5620c0f222/76576/pub2643stabilizingandbendingofwoodforthehobbyist20.pdf. Regarding drying time, if the sample is small enough weighing it at intervals will tell you when it is dry, ie. when it has ceased losing weight that means it has ceased losing moisture.

Can you please advise whether treated Victorian ash hardwood leeches tannin's after it is installed?

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Preservative treatment is unlikely to stop tannin from leaching unless the treatment process actually draws tannin out of the wood. Having said that, Victorian ash is at the lower end of tannin content being a pale coloured wood. As Wikipedia correctly points out, “Tannic acid is brown in colour, so in general white woods have a low tannin content. Woods with a lot of yellow, red, or brown colouration to them (like southern yellow pine, cedar, redwood, red oak, etc.) tend to contain a lot of tannin”. And tannin can only be leached out if water flows over bare wood, or wood with a permeable coating such as oil.

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