ok thanks. One side is still undeveloped and not sold yet ....... the back side doesn't come into play, since I am only filling up half the property and letting it slope down at the back.
How should one imagine the developed neighboring plot? How does it support its filled earth load? And how do you intend to hold yours? With L-shaped stones?
I know everyone tries to reach street level, but I know many houses here that are lower than the street. Entire street sections. We also have many dikes, houses often stand lower there, etc. And I can't imagine that they all have water damage.
We have several neighbors who have filled up to 2m, mostly not under the house but the property. Secured with retaining stones, planting rings, limestone blocks, etc. Costs beyond 30,000 euros... Better to have a basement and accommodate the granny flat there.
With a basement, the height fits. It can be built as a white tank, there is no water issue. Cost-wise, it's certainly similar to filling up an entire plot, compacting, sloping the edges, etc.
A basement usually costs around 60,000 euros for a single-family house. Therefore, the filling can already be worthwhile. There are still costs such as plastering, sealing, insulation, windows, ceiling, etc. to come.