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We’re working on a job for a beach house, which will have exterior timber cladding, batten screens and decking as well as some interior timber wall & ceiling linings, and interior timber flooring. We’ve received samples of a vertical cladding board ‘golden cypress’ (Macrocarpa) which our client really likes, and which meets the budget. We were hoping we could use it for everything except the flooring, for which we’d use cypress pine.
After talking to some other suppliers, we have some concerns about the durability of the ‘golden cypress.’
Is it suitable for use as an external cladding?
What’s the lifespan going to be like? Which rating figures should we refer to for our client to be able to compare species for the durability of a cladding?
Would cypress pine be better? We want a very pale blonde/silver appearance, will cypress pine go yellow?
Is it possible to get cypress battens to match the golden cypress cladding?
Is it possible to get cypress decking to match cypress flooring (not a perfect match, but a reasonable match.)

Woodsolutions Answer +

Cupressus macrocarpa (now designated Hesperocyparis macrocarpa) aka 'golden cypress' has a longer history of use in New Zealand where the better quality material is used for exterior cladding, sold under the name "macrocarpa". It's not included in Australian Standard 5604, Timber - Natural durability ratings, and therefore we don't have a Durability Class for it under the Australian system. An information sheet published by the NZ Forest Service in 1982 described the heartwood as "one of the most durable of all exotic species grown in New Zealand". However, they make the point that the pale-coloured sapwood, which can be distinguished from the yellowish-brown heartwood, is non-durable, as is the case for most species. In the past it was used for fence posts on New Zealand farms, so it would appear to have some in-ground durability. On the other hand, more recent advice from the NZ Wood website says "it is not recommended in-ground for construction purposes (including in-ground posts for fencing, decking and pergolas)". In summary, it seems it would be OK for cladding, but perhaps less durable than Queensland cypress pine which is suitable for use in-ground. Regarding your other questions, all timbers eventually turn a silvery grey colour where fully exposed to the weather and yes, cypress pine decking is available but will also change colour outdoors unless under cover. The same comment about sapwood applies to cypress pine - Timber Queensland recommends that "sapwood in cypress pine decking shall face downward and be below or as close as possible to any eaves or roof projection". 


I have read on wood-database american maple is much more dense and hard then rosegum but your information says the complete opposite. I'm just wondering who is correct ??

Woodsolutions Answer +

The American Hardwood Export Council states that the density of seasoned hard maple (aka rock maple, sugar maple) is 705 kg/m3 - refer their website here: https://www.americanhardwood.org/en/american-hardwood/american-hard-maple. The reference book Wood in Australia by K.R. Bootle puts it at 730 kg/m3. Density figures are averages and tend to vary a little from one source to another. Australian Standard 1720 Timber Structures, Part 2: Timber Properties, gives the density of rose gum as 750 kg/m3. Bootle, on the other hand, says that the density of rose gum "varies considerably with the maturity of the wood, with an average figure of about 620 kg/m3, although ranging up to about 750 kg/m3 for old growth". On our website we have quoted the American Hardwood Export Council's figure for maple, and the old growth figure for rose gum as per the Australian Standard. In fact it could be argued there is little difference between the two, depending on growing conditions. 

rose gum, American maple

I am making toys and functional ornaments from wood, and some of the internal components
require small slivers of wood that are able to flex a little for the mechanisms to work.
The plans for these projects are from the U.S., and they recommend ash or hickory for this purpose.
Are there any Australian timbers that would do the same job, and could be sourced from local merchants ( Bunnings, Home Hardware etc. ) ?

Woodsolutions Answer +

American ash and hickory (or their Australian substitutes) are not likely to be found at Bunnings or Home Hardware, you will need to inquire through specialty timber suppliers. For example, Britton Timbers have American ash, see website here: https://brittontimbers.com.au/timbers. You may find other suppliers by writing ‘specialty timber suppliers’ or similar wording in your browser. For potential Australian timbers we consulted an old CSIRO reference in our library to find a recommendation for wooden sporting goods such as tennis racquets, which need strength and flexibility. CSIRO nominates silver ash from Queensland which is also stocked by Britton Timbers according to their website. However, it comes with the rather negative comment that ‘English and American ash is still mainly used [for tennis racquets] and there is no really satisfactory Australian substitute’. Perhaps your intended use is less demanding than a wooden tennis racquet frame and you could try more readily available timbers such as the ash eucalypts, mountain ash and alpine ash, aka ‘Victorian ash’.

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