Stu,

The top and bottom of my existing tanks is just flat sheets that are
lap joined and riveted.

Since my last post I found some Australian Standards that go into all
the detail.

The std has a table detailing which metal types are incompatible
beacuse of electrolysis.

They do not differentiate between solid and pop rivets but do funnilly
enough mention self drilling screws!!!

Self drilling screws are a marvel of modern invention, I copied a
Stratco and Highcraft 6m by 6m ptiched roof patio a couple of years
ago and it is basically held together with self drilling screws.

I think I will probably find out off the manufacturer the shear
strength of solid rivets and see if I can get a pop rivet that is as
strong. This will make it a one man job.

The joints to join the top to the bottom are just the bottom cut a bit
bigger that the sides and folded up. Seal it generously on the inside
and away you go.

This sounds a bit flimsy but when you think of how the force of all
that water is distributed inside a cylindrical tank with the bottom
sitting on a concrete slab, the force of the water would be evenly
spread around the cylinder.

I am going to go to a tank shop and have a very close look at what
they have done and go from there. It worked for the Patio.


Its the vertical joint you have to worry about most(i think).
But copying it from the other tanks should get you there, best of luck.