Certainly, you can also break it down very precisely according to HOAI, but earthworks are generally counted as such because they are directly related to the construction of the house and leave very little room for how or what must be done. Outdoor facilities, however, can range from a gravel parking lot and a few paving stones to the front door for a few thousand euros up to the six-figure range for a "normal" single-family house, and that for one and the same house. The same applies to furnishings, etc. Therefore, the excavation pit MUST be done, as well as electricity and water, but certain curtains, lamps, or Miele built-in appliances do not.