Duplex or two-family house?

Your 300k equity is indeed a lot, but it also has to cover 2 residential units. That puts it into perspective again. I agree with the general consensus that the approximately 300 sqm will cost you around 600k. In addition, there are land costs, incidental construction costs, possibly a garage/carport, outdoor facilities, incidental construction costs, and furnishings. And 300k loan for 2 families is probably rather less. Most people here in the forum will have taken out over 150k.

That won't work. With that budget, only existing properties are possible. However, multi-family houses in the existing stock usually do not include apartments large enough for 6 people. Possibly a maisonette situation, but you will need a lot of luck to find something suitable there. Realistic new construction costs: Land 130k House 300m² 660k Additional costs / outdoor facilities 150k Total ~940k However, I also don't understand why the project isn't standing on two legs? Is the family with four children financially destitute?

Am I correct in assuming that the second family with the 4 children is only supposed to live with you as tenants? I also see the beauty salon critically. I think a good location is necessary there, parking spaces, etc., so that the property depending on the region quickly exceeds €130,000. What do the properties cost that you find interesting? The forum name suggests Frankfurt.

Wow wow! There is really a lot of life in here and also some truly valuable stuff. Thanks for that first of all. I can only learn from you.
As for the costs: Yes, a 400k loan would also be possible since I would have rental income. But that would really be the pain threshold. In the end, I don’t want to leave my daughter (who is still very young) a mountain of debt.
The future tenants are relatively poor. Yes, he works, but it’s just enough for the family + rent (if it’s not too high). We have already rented to them here and didn’t ask for too much. We want to handle it the same way again. The apartment here is now too small.
You have made good calculations. Under this premise, it will probably be an existing property when the time is right. For now, we will move into a rental anyway and take our time with our decisions. Maybe that one moment will come when everything fits. We will see.
Currently we live in the commuter belt around Frankfurt/Main, right.
All these abbreviations are still unknown to me as a layperson? Is there a legend for them here?
WR? MI? WA?

No are general abbreviations

WE residential unit
semi-detached house semi-detached house

Mi mixed-use area
WA general residential area
Wr pure residential area

Still felt unfamiliar to me. Thank you