General statement cost savings

Hello everyone,

I would be interested to know if general statements about the costs in relation can be made, for example:

1. fully basemented vs. half basemented

2. a full upper floor vs. an upper floor that is only half the area placed on the ground floor.

Please assume the same basic conditions in all cases and an average single-family house, with average conditions (location, soil, wall structure, etc.). I know it depends on many factors to make an exact statement. However, a rough orientation would already help me if, for example, one can say: "Half basemented costs about only half as much as fully basemented." Or is it rather that it no longer makes a big difference if you fully basement because certain costs are incurred once and then spread over more square meters with full basementing. So maybe it is more like: half basementing: 20TEUR, full basementing 30TEUR?

The same calculation would interest me for the upper floor. Do you save noticeably if, for example, in Bauhaus style with a flat roof, you have a 100 sqm cube as the ground floor on which you place a 50 sqm cube as the upper floor? Compared to 100 sqm ground floor with 100 sqm upper floor?

Many thanks

For "general statements," I can repeat what has been told to me several times on the topic of [Keller]:

Partially basement:
Either you build with a basement or without. The additional cost for a partial basement is relatively low.

Basement or not:
If you need the gained living space and the plot is limited in size, you choose a basement. For pure storage space, a basement is too expensive.

Costs for a basement:
Depending on size and requirements (waterproofing, insulation, windows, ...) very different. When comparing, don’t forget that the alternative slab foundation is not free either.

Basement surcharge for most single-family houses probably between 30 and 50k€.

We need the space, so we planned with a basement. It will be cheaper than an additional full floor (if even allowed).

Regarding the attic: The surcharge here will also be low or at least not proportional – with increasing size, the ratio of building envelope to volume improves. However, follow-up costs must also be taken into account here: floors, interior walls, plaster, etc.

Thank you Frank, that is already a helpful statement.

... and Frank's information is correct

Rhineland greetings

Oops - I should have read more carefully beforehand ...

The statement "Wird günstiger als ein weiteres Vollgeschoss (wenn überhaupt erlaubt)" is of course nonsense. Sorry

Rhenish greetings