Going up! Raised deck for a greenhouse.

We need a barn/ shed at our pico farm. We want a greenhouse as well. The southern exposure is hampered by
I am currently considering a raised deck , with a greenhouse/ shade structure on top, and solar thermal storage/ rocket stove below.
Because they are cheap for me to by,I am planing on using IBC totes as the piers.
Stacked two high, when they are rated to carry a third on top of that, they should be able to carry anything I ask of them.

What kind of "foundation " should I make for them? I could just keep the bottom IBC filled with water or rocks, but I would still want to level them and prevent settling.

Any ideas or objections are welcome.

That's a cool idea! If you get it done I would like to see photos!

Is your soil comactable, or do you feel like you need a structured footer to handle the wieght or stabilize it?

Thanks for the interest!

The soil is largely clay, with bits of building rubble...I have serious trouble digging in it, so I think it qualifies as compactible!
Honestly, i am leaning towards a rubble trench , to aid in leveling and so the steel won't have water sitting right under it, but with huge weight and a 40 "x48" footprint, I expect them to be very stable.

I have seen one photo of a military building made up of two parallel walls of these totes, wooden roof trusses spanning the space between them.
I lost track of it and my search fu has found pretty much nothing on building with these IBCs.
If I complete it, I want to post photos and learn to point search engines to it.