Planning a multi-family house - optimizing costs

One thing I don't understand: The money from your mother would be enough for a bungalow. Aren't her apartment plus 2 others more expensive?

Hello everyone,

the feedback is coming in incredibly fast. Thank you very much for that

@ ypg: Since my mother's apartment is "oversized" for a single person and you can't really rent out 120 sqm for the full price, we want to divide the floors into 2 apartments each. So definitely the 1st floor and the attic if it’s worthwhile and approved in terms of the number of apartments.

The property is 550 sqm.

@ 11 ant: My mother bought the property "blindly" for her bungalow. It wasn’t my idea and I wouldn’t have done it either, but she really wanted to. Since properties are very rare here, she bought quickly and without checking.

That "if-if" [hätte hätte] worst-case scenario could happen. The floor area ratio is the buildable area, I assume? It is actually 0.4. In this old development area, only 2 apartments per property are allowed. At the same time, there are several buildings with 3 apartments and about the same floor and plot size, or an equally large plot on which 4 townhouses have been built. We would probably be able to achieve the area with a 0.4 floor area ratio according to the developer.
I am currently trying to get in touch with the district master builder to discuss our plan with him, as the municipality referred me to him. Due to the fact that housing is in high demand here and there are various exceptions in the development area, I hope that we will get approval for 4, better 5 apartments on the plot.

Thanks for your lively questions.

One thing I don't understand: Your mother's money would be enough for a bungalow. Aren't her apartment plus 2 others more expensive?

Yes, that's correct. The price per m2 compared to the bungalow is already significantly lower at the €2900 we're currently talking about, and with my equity and loan I would partly finance her, so to speak, crosswise (since she also paid for the land).

The 2000 per m2 are always without additional costs and without basement. The 2900 per m2 are average.

The floor area ratio is the developable area I suppose?

Developable area is the site coverage ratio.
Floor area is the floor space index.

According to the developer, we would probably manage the area with 0.4 floor area ratio.

0.4 of 500 is 200 sqm total area in all full floors.

If your mum claims 120 for herself, then 80 sqm of full floor area remain.
’s question is justified: what does the development plan say? So far I would say: not possible.

Due to the fact that housing is in very high demand here and there are various exceptions in the development area, I hope that we will receive approval for 4, preferably 5 apartments on the plot.

Housing is not in such high demand in any municipality that one would be willing to have the basic principles of a development plan apply only during a full moon. I regularly see an exception possible for 30 instead of 28 degrees roof pitch, but allowing 5 instead of 2 housing units is a very stretched interpretation of "letting things slide." Name the exact framework conditions of the development plan, but until proven otherwise, I consider the plot only sufficient for half the volume of the desired construction project.