Building plot: Massive fill or better basement with excavation?

Thank you. And what costs are realistic if you fill up a hillside plot up to 3m with recycled gravel and build on it?

The civil engineer was of the opinion that this is cheaper than a basement including excavation), because the gravel is cheap, less excavation is needed, and no lifting system is required.

Because you simply don't build a bathroom in the basement. If you don’t have a basement, you also don’t have a bathroom in the basement. And with that, the topic of a lifting station is off the table. What I forgot to finish writing earlier: The condensate drain of (for example) a gas heating system can also be collected in a canister and then has to be emptied manually from time to time, so heating in the basement is not necessarily a reason for a drain in the basement.

Why shouldn’t clay-containing soil be backfilled? Currently, it is naturally backfilled in the ground anyway. A layer of clean topsoil on top, possibly a thin sand layer underneath as a drainage layer between clay and topsoil, so that it doesn’t become a swampy garden.

If you build without a basement and see the hole the guys are digging and then the bill for the earthworks and 500 tons of mineral mixture (that’s not as much as it sounds; around here, over 200 tons were also used in very gentle slopes and for construction roads, etc., and you can hardly see any of it), then you’ll regret not having built with a basement.