Multi-generational house with underground garage for 3 families

Hello everyone,

after being a silent reader here for quite some time and really liking the ideas that come together here, I would also like to bring up a topic and hope for ideas, suggestions, etc.!

I am 34 years old and come from Munich. I was born and raised here.

Currently, we (my wife and I + soon a child, my sister and her partner, as well as my parents) are discussing whether to completely rebuild on our property (currently built with a single-family house / 1000 sqm / 20 × 50m / no development plan). The idea is that the building will be a fairly modern house with two generous areas each (each with a terrace to the garden, large living and dining area, etc., and about 200 sqm of living space) including an underground garage and a basement. A granny flat is also to be integrated.

I would like to start a discussion with these approaches and am curious about ideas/criticism etc.

Thank you very much.

So you want space for your parents, your sister with her family, and yourself with your family, right?

I see several sticking points: depending on the orientation of the property, one half could be less attractive. Who should take that - voluntarily?

The sister’s boyfriend would have to be excluded from the financing. At least that’s how I would do it in his place if I didn’t own any part of the property. But what is he then allowed to decide on in the planning, or how will he participate financially in the future?

Have you also talked about everyone’s expectations regarding possible future care?

How can you mitigate the risk if one of the borrowers defaults? How do you want to handle it at all – everything separate from the technical aspects to the finances or one big pot?

Hello Maria,

thank you for your comments and suggestions.

The situation is indeed as you described. The alignment could probably be a point that might be somewhat difficult. Here, I or we have corresponding expectations of an architect.

My sister’s boyfriend should have an equal say, as further plans (wedding, etc.) will probably be carried out soon.

Fortunately, financially it is possible for us to manage the financing without a loan, and this could be done jointly from a large pool. I actually rule out any disputes or problems entirely.

The care, for example of my parents, is already arranged to the extent that we don’t have to think about it.

Actually regulated

Separates everything cleanly. Now finds a clean regulation for what would happen if.
Unfortunately, it often happens that siblings no longer speak to each other. After that, every cent, every minute of work is calculated and contested.

Has it also been considered how it could play out in the worst case "sister dies/ her husband inherits and falls in love anew"?

Worst case has not been discussed like this yet. Absolutely important point, though! Thank you!