Quote:
Originally Posted by Startrek
The major pro observatories of the world sit on concrete structures 5 to 10m metres thick...
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The major pro observatories of the world sit on concrete structures 2 to 3m metres thick.
The major pro telescope mounting systems (piers) of the world sit on concrete structures 5 to 10m metres thick.
The use of "damp proofing" (look it up, usually a layer of plastic like material) under the slab stops moisture moving into the slab. Even a concrete pier really requires damp proofing.
Speak to a qualified builder.
Having said that I used steel RHS for floor joists around a tri-pier system.