Garden house foundation: slab, strip foundation?

A strip foundation is therefore mandatory? On YouTube videos, I see garages and garden houses without strip foundations. I thought I would dig 80 and fill it with recycling and other material, lay XPS on it, and then a 30cm reinforced floor slab.

Hello knock88

whether it is mandatory for you or not, I cannot tell you: I would do it that way. A 30cm base plate is of course also ok. I think you are doing it right.

Steven