Thread: Shed posts, advice on timber choice please.

At 300mm and not in the ground they are going to be good for years.

Probably not the best. Is suseptable to dry wood borer attack. Lyctus love it. Poor fire rating.

A shed is a shed.
If you aren't putting them in the ground, if they will not be wet, i.e. the roof will totally protect them from the weather, if you spray them with borax or something, I think 300mm wide would be fine.
Put them around 2.5-3 metres apart, use second hand corrugated iron to cover the sides that the rain will come from...
I assume you will be using them for cross beams as well? Again, they will be fine as long as the span isn't too wide. Use only clean logs for the cross beams
Spray them or soak them or something, I don't know what is the best here.
Fire risk? All woods are fire prone, but that is another matter and if you only want a rough shed to dry timber, if it lasts only lasts 30 years.... and does the job for that time and it is basically cost free.... go for it.
Greg

Thanks for those thoughts, Lyctus don't seem to bother with these logs. Indeed termites will attack the sapwood of dead trees that have been standing for 5 years yet past the sapwood it will be totally sound.

Fire risk is not so much of an issue as we just do not seem to get fires here.

Greg, you are correct I was going to use them as cross beams also, however I was hoping to be able to have wider spans, to make getting long lengths of timber in and out a bit easier. So I had started to think about corner bracing at the top, rather than using bigger cross beams. I wonder if 6m is realistic or am I dreaming?

I saw/read somewhere that timber in the round is much stronger (when compared to sawn timber) than the difference in size/volume would suggest. Not being an engineer I'm not too sure what to make of it, but it does have a sort of bush logic to it. Does anyone have any thoughts on that?

Lyctus only presents a problem when the celulose level in the timber is to their liking. When using less than ideal timber for posts its not a bad idea to design the shed so that you can jack adjacent to the post for removal and replacement should it become necessary.

Gonetroppo,
I'm thinking that a 300 dia section of black wattle spanning 6m is no problem. Providing there are no faults/knots in the log. I have some good quality 8x2 flooded(rose) gum sawn beams in a shed spanning 7m OK. Right on their limit I admit and not really to the code but not sagging after 10 years. Bootle lists the Mod. of Rupture for both Rose Gum and Black Wattle at around 122 MPa. so their strengths are comparable.
I see sheds around here with tiny 100mm dia flooded gum saplings spanning 4m. Provided they are protected from the weather and termites they last for a long time.
Rgds,.
Bill.