What posts for heavy fence panels?

[michelf]

Hello, I am looking to construct a 300m long fence using a sandwich panel made of calcium silicate skin and a concrete/polystyrene core. The fence bays will be 1800mm high 2200 long and 50mm thick. (Three pieces 600mm high stacked tongue and groove). The lower piece will rest on the ground each piece is approx 50kg, so at 1.8 high, is 150kg per fence bay.

I am looking at post options to support this. At 50mm panel width the colorbond post and rails are a great size for, however I am concerned over the weight on these posts. Do you have any suggestion?

Thank you

[MitchellMc]

Welcome to the Bunnings Workshop community @michelf. It's wonderful to have you join us, and many thanks for your question about building a fence.

Are these panels designed for use in fencing? If so, I would have thought the manufacturer would have some specifications you could work to for the construction. If not, I suggest an engineer assist you with the size of the post and footer. Quite a few calculations and soil tests need to be done to give you a quantifiable answer. I presume it might be a 30m fence and not a 300m fence, but even then, there will be 14 bays at 150kgs each. That's over two tons of weight, and your posts and footers really need to be designed to withstand the wind shear forces applied to them. 

Unfortunately, Colorbond posts are specifically designed to be used in a system with their lightweight panels, so the manufacturer certainly doesn't advise using them for other purposes.

Please let me know if you have any questions.

Mitchell