Guys while patiently waiting for my pier I have decided I may as well keep going and build a ROR obs to keep it cosy

. I am currently in the planning phase and looking at my options to clad. Currently the plan is to clad it first in ply then screw the colour bond cladding over the ply. Are there any drawbacks to this or any thing else I should be adding between the colourbond / ply or the ply / frame ?
Thanks..
Mark