Hall floor for tiles with "solid feel"

[mattie_river]

Hi! After water damage, the wooden floor in the hallway has been removed. Now I want tiles on the floor with a "solid" feel, i.e. not laid on boards.

The house, built in '44, has concrete joists (quite thin) with a very rough top side. On the joists, there have been battens with wooden flooring. Under the wooden floor, there has also been sand.

My idea is to have about 4-5 cm of EPS concrete, 4 cm of floor leveling compound with reinforcement mesh on top, and then tiles on top of this. See image.

Grateful for opinions on the above. Is it unnecessary to have EPS at the bottom? Thinking it might otherwise be a bit heavy.

 

[WaldenWoods]

You say floor structure - so this is not on the ground floor? Or am I misunderstanding?

 

[mattie_river]

It's two flights up.
Update: Considering skipping EPS and just using thick self-leveling compound. The concrete substrate is so insanely uneven that the total thickness, excluding tiles, would need to vary between surely 10 cm and 5 cm and the top slopes quite significantly. And many large stones as ballast protrude. And by "fairly thin" concrete slabs, I mean about 13 cm of reinforced concrete, but it's hard to say precisely as the top is so uneven.

The first picture shows the edge of a layer of self-leveling compound that is 1-3 cm thick depending on the location (it's a hall with the only entrance, so we have to do it in stages).