Floor plan design single-family house (city villa 140 sqm) on a slope with double garage

They are not. I had also written that to him. Still, 220 sqm for 450,000 is more realistic than 140 for 250,000 You have many costs that occur regardless of size or do not increase linearly. You cannot say house costs: 140 x 220 = price big house

They are not. I had also written that to him. Nevertheless, 220 sqm for 450,000 is more realistic than 140 for 250,000. You have many costs that are independent of size or do not increase linearly. You can't say house costs: 140 x 220 = price of a large house

I am aware of that, but then a value of 400k +X does not fit for me. The initial situation is very similar and the other is a significantly larger house. All the areas also have to be equipped qualitatively.

The truth probably lies somewhere in the middle. I would have placed your project at about 350K Euro. At the moment, though, everything is still just guesswork.

I am already aware of that, but a value of 400k +X just doesn't fit for me. The initial situation is very similar and the other is a significantly larger house. Also, all the areas have to be equipped with quality.

Don't worry about it. He won't get far with his 450k€. Just the balcony with thermal decoupling of the base slab costs 6000€ net for 6x3m without columns. The 2x plus columns, railings, drainage, coverings, etc. This measure alone costs 30k€. Then 220 sqm in residential quality 440k€. Plus incidental construction costs and suddenly there is definitely a 5xxk€ in front of it. Your 400k€ completely includes everything (also a brick facade) without kitchen, only the garden and fence still need to be done, and if you're frugal, the kitchen is even included.

...I also planned to expose the basement and build a raised terrace on the ground floor. Unfortunately, I had to abandon this. Even though this would have eliminated the need for L-shaped stones and backfilling, I would have had to remove and dispose of about 900 sqm of "loose soil." For Z0 soil, I had a quote of €23,000. The terrace would have cost another €30,000. In addition, the basement side would need extra plastering, stairs down to the garden. Still, L-shaped stones to support the carport would cost €10,000, and so on.

However, since the soil analysis showed Z1.1 soil, the earthworks and disposal costs would have tripled. That put the beautiful idea down the drain.

Here you also quickly realize how important a soil analysis is. If the analysis is only carried out at the disposal site, then in such a situation you have already "lost."

What you could possibly still do is find out the actual figures for the ancillary construction costs, especially for the costs that are independent of the floor plan. For example, Telekom which wants almost 800 euros, Stadtwerke etc.