Plan for outdoor facilities created by yourself, experiences?

Grey for splash protection, which is completely missing here

Oh, I had forgotten to mention: Around the house, according to the warranty specifications of the main contractor, 20cm of gravel must be applied as splash protection. That is the black edge with the fine white dots.

Is there a floor area ratio? Is it being complied with?

I theoretically have 0.8, the sealed area would be 0.5, so about 50%