Property development - basement yes or no?

Building envelope and plot are sufficient for a double carport and house on a slab foundation. I see no compelling reason to build a basement. With a basement, the budget would be quite tight in my opinion, and you always have to worry (also depends on the location and requirements). Without a basement, it should work well and you won't have sleepless nights. For the family with 2 children, a house on a slab foundation is completely sufficient. If needed, the attic could be used as an expansion reserve.

They say, the smaller the plot, the more likely you should build with a basement so that some garden remains. But first and foremost, the budget for the house must be sufficient.

We are very uncertain about what is the better decision for our plot: (partial) basement with a smaller floor plan (approx. 130 – 140 m²) (Option A) or slab foundation and a somewhat larger floor plan (approx. 170 m²) (Option B).

I do not yet see any fundamentals here for the application of my basement rule or an indication that the decision is even open to you. For partial basements, use the search function for "Teilkeller" "from: 11ant". Assuming the delta of 170 vs. 130 sqm (i.e., 40 sqm) is the space requirement of the questioned basement, then that would be a 31 (46)% partial basement under a one-and-a-half- or two-story building. We are talking about approximately 60 to 70% of the cost of a full basement (possibly plus terrain construction costs if the plot were to vote for a basement).

We built a detached house with 150sqm and a basement 2 years ago and would definitely do it the same way again.
All the technology including washing machine+dryer is housed in a room >20 sqm and there is plenty of space in this room.
In the storage room (>25sqm) there is simultaneously a foosball table and a play area for the children (Lego, slot car track etc). We had laminate flooring installed here.
Additionally, we have a study (15 sqm) and a guest room (13 sqm) in the basement.

This would certainly have all fit in the upper floor as well. However, with our small plot (<600sqm) I would have lost too much garden space.

In our site plan it says "Extract from the land registry" but unfortunately I don’t see any contour lines there. I think I’ll try my luck with a water level. The development plan generally doesn’t say anything about required parking spaces – therefore I assume that’s not a problem. But we would definitely prefer a double parking space anyway. Thanks for the assessment – I think the garden area would be sufficient for us. The garden would also go all around the house. I don’t quite understand yet. Why shouldn’t the decision be open to us? Do you mean because the soil report is not there yet? Thanks for the tip about the partial basement. We weren’t aware of that. Does that mean, on the other hand, that a partial basement is not really worthwhile in terms of price/performance? Thanks for your experience report :) What ceiling height do you have in the basement?

@11ant I don’t quite understand yet. Why shouldn’t the decision be up to us? Do you mean because the soil survey is not available yet? Thanks for the note about the partial cellar. We were not aware of that. Does that mean, conversely, that a partial cellar is not really worthwhile in terms of price/performance?

You don’t make the decision alone; the plot of land more or less speaks – how loudly, I lack the indicators here, as I said. From a business perspective, partial cellars are textbook examples of inefficiency in square meter “unit costs.”

Okay, the idea of partial basement construction is off the table then ;). I found your basement formula: "for every 20 cm of terrain height difference within the building plot, ten percent of the basement price also for not building it." So you're missing the information on whether it refers to terrain height differences or not? Unfortunately, in my excerpt from the real estate cadastre, no contour lines are drawn, but I found something in the development plan. In the explanation of the development plan, I find: and in the development plan directly on our property, the following information: I know it's unfortunately very hard to read... but maybe it helps?