# Forum Home Renovation The Cubby House  Using fresh spotted gum trunks for posts?

## boo

Hi All, 
I have some fresh spotted gum tree trunks that were very recently felled to make a fire break. I would like to use them as posts for a cubby house - they are 150 - 300 mm, and I'm leaving them round and rugged.  
Obviously the timber is still very green (they were alive until chopped down), so: 
1) What issues should I expect if I use them as corner posts for an elevated cubby with deck? 
2) How can I eliminate or minimise the effect of these issues (apart from waiting 2 years for them to dry out...) 
Note: at the base they will be encased in concrete. 
Thx.

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## Moondog55

OK if nobody else can help I can think of a few things.
Debark quickly to stop grubs eating into the cambium layer.
Cut away all of the sapwood where it will be in the ground, 
Then burn ( char ) the ends. 
Don't know anything about the green strength of spotted gum so how big are these?/ How high and what diameter deducting about 50 mm for the sapwood and shrinkage??
Minimum top diameter for poles for load-bearing structures ( also kids swings etc ) is about 150mm if they are smaller than this I'd use them for firewood

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## boo

Thanks Moondog, that's good info.   

> How high and what diameter deducting about 50 mm for the sapwood and shrinkage??

  About 3m. i.e. 0.6m in ground (hits rock), 2.4m above. 
Diameter is up to 300mm total at present, so once cleaned up they'll still be sizable sections - just hope I can handle them :Yikes2:

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## Moondog55

Rule of thumb is 1/3 of the post in the ground, you will need to dig deeper holes or get some expert advice on this.

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## boo

Yep I agree in principle for isolated posts, but these should act more like pole home piers. BTW, I don't know of any 2.4m high cubby house/play structure/etc that has posts going down 1.2m.   :Erm Smile:  
Anyway, cutting 300mm+ core holes in rock is prohibitively expensive, so not going there. 
I'm erring toward doing this with reo'd concrete piers from rock to ground level, with a metal plate on top with bolts into the posts. This will keep all the timber above ground and inspectable, as well as minimising the effect of shrinkage on the foundation. 
Better get on to that debarking ...  :Smilie:

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## Moondog55

Probably not, I maybe wouldn't either, but that was what i was taught at school.
I did dig that far down for my shade sail posts and it was seriously hard work, put them in 32MPa concrete too. 
maybe you can get a sandpit in the base as well, nice and shaded in the hot weather. 
Good luck

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