New construction outdoor area single-family house solid

Why the thread was even started interests me too :-) You don’t seem to have any questions nor are you looking for suggestions. Also, responses tend to be unmotivated and monosyllabic. But well, through the comments I at least feel well entertained :D

No bicycles are allowed in your room "Garage." You keep hearing about the most bizarre rights in Germany. You can google it, but it might only be relevant for tenants...

Why are high costs assumed.

Because you have 300m² of floor area. That requires so much earthwork and a roof area, you could just as well build two separate single-family houses.

An area made by a carpenter is also only common in the upper range:

The whole thing is an area made by a carpenter.

Aside from that, things that are built and then not needed cost not only money but also waste it unnecessarily, e.g. stairs and two of them at that. Otherwise, I repeat my question from #12:

Gab es zu diesem Grundriss eigentlich auch konkrete Fragen?

Why are high costs assumed.

The house area is like a bungalow with 170 sqm.
The garage has 80 sqm.

Whether I insulate the garage with 60mm or 160mm doesn't make a real difference.

Here is an example where you are mistaken, and even I notice it as a layman:
According to the drawing, the garage is within the thermal envelope. That means the garage door must be insulated and airtight. I am sure there is such a garage door somewhere in the world, but nothing off the shelf for sure. People who want to take their Ferrari into the house usually build that.
If the garage is within the thermal envelope, you will also need a ventilation system for it. Otherwise, everything will rot if you bring in moisture during winter. Again, a point that is significantly more expensive than a normal garage where you can just tilt the window.

Overall, for the garage we can assume more like living space, i.e. €2000/sqm. Living space in the bungalow is certainly a bit more expensive, so let's say €2500. That totals about €580,000 just for the building. Certainly, you can reduce the price considerably through your own work, but your fittings don't sound cheap either. Therefore, I would initially leave the sum as a rough figure.

You have no questions. I do:

Roof shape?

Roof pitch?

Plot plan?

Slope?

Connections?

Terrace? Covered?

34er?

Development plan?

Development in the area?

Budget?

A bungalow is more efficient and certainly also more practical.

Now it's your turn.