Are ancillary construction costs for a single-family house realistic?

Without a basement, that should of course be enough. But do yourselves the favor not to store the excavation material on the side depending on the soil condition, as is often offered. Have the stuff taken away immediately if it is not suitable for backfilling, otherwise the excavator will have to come twice just for that. Backfill sand costs practically almost nothing (with us about 70-80 € per truck), without a basement you will need max. 2-3.

Insofern wird das Maß der Erdarbeiten überschaubar bleiben.

It can only be finally assessed after the soil report (and with the house plan or the structural analysis). If necessary, a cistern or soakaway may still be added.

One can only make a final assessment after the soil survey (and with the house plan or the static calculations). If necessary, a cistern or infiltration trench might still be added.

Also correct, yes.

You can only make a final assessment after the soil survey (and with the house plan or the static calculations). Possibly a cistern or soakaway will be added.

My 10000 plus 5 refer to without basement and with rainwater cistern.

Just learned from a reliable source ([neighboring property]) that excavation was done there at a depth of 1.2 m and about 1 m of fill sand was installed. Can someone tell me approximately how much the costs for these works are? We have an offer that includes excavation of 80 cm in the price. Can one roughly estimate how much extra you would pay for the above-mentioned values? Regards

We paid about 70-80 € for a truckload of fill sand. So if you need to fill approximately ±100m³, that would be maybe 6-7 trucks plus "installation," which should be relatively easy and quick. WE ESTIMATED that we would have paid our excavator about 1500 - 2000 € for that (for filling! Excavating and disposing of 100m³ would then cost another 1500-2000 €).

Alternatively, just have it excavated, have sand delivered and spread it yourself and compact with a vibrating plate.