Adding 2 more pics. This shows how I installed the bottom layer of rebar for the suspended slab. At first I used stainless rebar with 15 cm spacing, but then I started doubting because stainless rebar is less rough (meaning it doesn’t bite into concrete as well as regular rebar). So I added glass fiber in between, which makes it now 7.5 cm spacing.
Originally I planned to pour two separate small slabs, in which case the suspended slab would have needed reinforcement only at the bottom. Later I decided to pour a continuous slab over the middle load‑bearing wall, which requires two layers of rebar. The pics also show the ventilation openings and the toilet shaft opening.

