Rough planning exterior - elevation relationships

By supports I mean the beams on which the floorboards lie. But that looks like normal soil underneath. Is that very dark gravel? Did you excavate and put gravel or pebbles underneath?

we set the edges with L-shaped stones, filled with sand (there was plenty around the house), compacted and aligned, grass grid stones as supports, WPC beams on top with rubber pads underneath, and on top the decking boards (closed deck), 1% slope away from the house and sideways, laid parallel to the house

By supports I mean the beams on which the floorboards lie.
But that looks like normal soil underneath. Is that very dark gravel? Did you excavate and put gravel or pebbles underneath?

The substructure must be 40x60. They are screwed onto simple terrace slabs on adjustable pedestals. The entire area is excavated and gravelled, and on top of that there is weed control fabric.
Because of the cross battens, the whole thing is super stable, but in the end it was also quite complex and expensive. Apparently, it is not often done this way. Well... hindsight is always 20/20 :p
From today’s perspective, we probably would have had foundations poured. That certainly wouldn’t have been more expensive.