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Question

May I know the recommended hardwood species and its longevity used for play equipment framing & random logs at the nature playground area? Ideally we would want them to last longer however some of the logs tend to progressively worsen over time.

Woodsolutions Answer +

Class 1 hardwood species in ground contact are expected to last more than 25 years, according to Australian Standard 5604 Timber - Natural durability ratings. The Standard doesn't give a precise number since actual service life depends on factors such as rainfall, local termite activity, etc. The 'probable' service life of 25 years + could be exceeded by a significant margin. Class 1 species include ironbark, Gympie messmate, grey box, sugar gum and tallowwood. Some of these species might not be available in log form, or might have to be brought to Victoria from interstate. To broaden your range you could consider Class 2 species which have a probable in-ground service life of 15 to 25 years. Note also that logs are not likely to be fully seasoned and would be best installed during autumn/winter when they can continue to dry in situ. Unseasoned logs put out in hot sun are prone to developing splits. For guidance on using round timbers you may find our Technical Design Guide no. 47 useful. It can be downloaded here: https://www.woodsolutions.com.au/publications

Playground equipment

Answered on 27-11-2020
Please note that our answer is based on the best advice available at the time. If the National Construction Code, Australian Standards or local requirements have been subsequently amended, our answer may no longer be correct in all details. For more information, please read our disclaimer.

Question

I have an upper storey on my house, added late 80s early 90s by previous owners. The exterior walls of the upper storey are fibre cement sheet (not asbestos) and the joins of the sheets (butt or angles) and the edges are covered with painted timber battens. The battens also frame the Stegbar cedar windows. Apart from a bit of minor furring in a couple of small areas the windows are OK. I think the timber battens are Meranti or Pacific Maple or something. The battens have rotted (and are about to rot!) in a number of places and I need to replace them. The battens are 19mm by 110mm. The house is in Maroubra, a coastal suburb of Sydney about 250m from the cliff face onto the ocean and salt spray and sun are a consideration. Access for replacement is a real pain and it's a fiddly job so I don't want to have to get it done again. Labour is likely to be the biggest cost driver in replacement. Question: What is the most durable timber to use in these circumstances? 

Woodsolutions Answer +

Your experience has shown that western red cedar is much more durable outdoors, above ground, than meranti aka 'Pacific maple'. If the meranti battens were installed some 30 years ago they have significantly outlasted their expected life span. A suitable replacement timber would be cedar, since it has already proven its performance in your location. The furring you noticed on the windows might have been caused by salt spray, with salt subsequently forming crystals in the wood, rather than wood rot. Durable kiln-dried hardwoods (tallowwood, spotted gum, etc) are also a viable choice but less dimensionally stable than cedar. Whether you choose cedar or one of the hardwood species it's recommended to pre-paint the battens with a complete envelope, Water entering the interface between the back of the battens and the fibre cement will affect the performance of any timber, possibly causing warping if not hastening decay. And make sure the contractor uses stainless steel fasteners in such an exposed location.

Durable timbers

Answered on 17-11-2020
Please note that our answer is based on the best advice available at the time. If the National Construction Code, Australian Standards or local requirements have been subsequently amended, our answer may no longer be correct in all details. For more information, please read our disclaimer.

Question

What timber is the best option of bearer and joist system for a single storey house from your experience?

Woodsolutions Answer +

The best option for bearers and joists is seasoned, stress-graded timber. Unseasoned ('green') timber will shrink as it dries, possibly leaving a gap around the perimeter of the floor between the skirting and the floor surface. The type of timber is less important. As long as the sizes are suitable for the required span, it doesn't particularly matter whether you use softwood or hardwood. We assume that other factors such as termite protection and sub-floor ventilation have been taken care of and comply with National Construction Code requirements.

Bearers

Answered on 12-11-2020
Please note that our answer is based on the best advice available at the time. If the National Construction Code, Australian Standards or local requirements have been subsequently amended, our answer may no longer be correct in all details. For more information, please read our disclaimer.

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