Single-family house + granny flat on a slope with flexible use

There are even 6 roofs. The parking area under the carport roof also needs to be sealed and drained, since the cellar is still underneath.
You should directly make a cost comparison if you were to build a garage instead.

Ok, I had never thought about it that way before, but I would also never have guessed that. I thought the financial difference would be about double.

I see a plot area divided into two parts in depth (12 m + 4 m), additionally add the details TH (B), TH (T) etc. or better yet, please state the name of the development plan (Xdorf No. 123, external links are not desired here).

Furthermore, I see contradictory representations (in the development plan excerpt the embankment lies between the street and the plot area, whereas in the elevation plan it lies further inside the property).

I have mostly been a silent reader here for several years

Then hopefully you have seen that your project’s property profile is less comparable to that of , but unfortunately rather comparable to those of or even more so .

I see here a “rich uncle from America” required just for terrain adjustments, with the “rest” then available for building the house. At you can also admire such a dream property, and there I also saw a fully basement garage.

(Secondary apartment = relief at the beginning when salaries are still lower)? We still need the rooms from the secondary apartment for the future desire to have children…

Especially with “rather three than two children” I see one of the salaries reduced or disappearing, simultaneously with a loss of rental income …? — you notice that yourself, don’t you?

At least I understand the budget such that the property is already taken care of and the money after the terrain modeling must “only” be enough for the house. But it will probably still be tight with this property profile.

I agree with Thies (11ant) and would claim that unfortunately your design will remain a castle in the air. Your mega hangar is indeed beautiful but really expensive. Cut out the granny flat and start over - preferably with measurements on the building.

With two children, the small room might still work, with three it doesn't. You are planning for 2-3 children.

A balcony is no substitute for a garden.
You pack a diaper, burp cloth, play mat, rattle, drink for the toddler. Carrying everything like a donkey to the garden. You wish you were an octopus with the strength of the Hulk. After 15 minutes you realize you forgot your water. Baby is crawling, toddler is climbing. You have to leave your children alone now. No quick trip to the kitchen and keep an eye on the kids.

Can only agree with 11ant.
Get rid of the granny flat and get a smaller new one.

Calculate 50k instead of 15k for the outdoor area. The retaining walls alone quickly swallow 30-40k, 10k for the exterior stairs, ...

Such a site just screams for living in the basement with direct garden access! And you can make it so nice. I think you need to go to a proper architect. Slope houses are not easy...