How thick should you pour a floor over a basement

[valjn]

How thick should I pour the floor over a basement hallway that has 1200mm between the walls that the slab rests on? Is 70mm enough if it is well reinforced?

 

[Plupp 405730]

How thick should I cast a floor over a basement passage that is 1200mm between the walls that the slab rests on? Is 70mm enough if you reinforce it well?

What do you have under the floor?

 

[valjn]

What do you have under the floor?

The basement underneath is also made of concrete.

 

[valjn]

What do you have under the floor?

More info
The hole is in a corner of a regular room. 1200 x1200mm like a lid over the hole.
The lid is both the floor above and the ceiling below.

 

[Plupp 405730]

More info
The hole is in a corner in a regular room. 1200 x1200mm like a lid over the hole.
The lid is both floor above and ceiling below.

Ok, then I understand a concrete slab. How thick is the rest of the slab that you are casting against?

 

[valjn]

Ok then I'm with a concrete slab. How thick is the other slab that you're casting against?

Not cast yet but probably around 100mm.
Casting everything at once.
Chosen 70 mm to be able to go under it.

 

[Plupp 405730]

Not cast yet, but probably around 100mm.
Casting everything in one go.
Chose 70 mm to be able to go under it.

70mm sounds thin, concrete slabs/floors are usually 120-200mm thick in single-family homes…
I don't think 70mm will hold, depending a bit on the load…