Construction costs for multi-family houses in Baden-Württemberg

Hello

I have the opportunity to build a multi-family house with a total of 700 sqm of rentable living space on my own plot of land in a very good central location (900 sqm / value approx. 500,000), rural but in the outskirts of Freiburg. I would choose a medium standard in order to be able to rent it out solidly in the long term. The current building plan does not require an underground garage; normal car parking spaces are allowed.
I have two questions. How much in euros per sqm construction costs should one roughly calculate for a medium standard (no luxury)? Prices seem to be very high at the moment. "Complicating" the calculation of the return is the fact that land prices are very high. This is complicating because selling the plot in the long term is not an option for a number of reasons, including tax-related ones (impending commercial status). If I assume, for example, 3000/sqm and include the current market value of the land as equity, it does not seem like a good deal, at least from the perspective of a possible resale in the distant future. And how is it best to divide the 700 sqm into residential units? The trend now seems to be moving back towards smaller living spaces for 2-person households?

I would be very grateful for your help!

Best regards!

Definitely a project to discuss with an architect. All in, I would estimate around 2 million.

And how is it best to divide the 700sqm into residential units?

At least not into equally sized ones.

I would choose a medium standard in order to be able to rent solidly in the long term. The current building plan does not require an underground garage,

An underground garage would especially not be "medium standard." But above all, any standard is wrong if there is only one. If there is a penthouse or maisonettes, the highest standard belongs there, otherwise on the main floor. With true ground level, I would provide an accessible residential unit.

The trend now seems to be moving back towards smaller living spaces for 2-person households?

Trends are usually significantly more short-lived than building loans.

The project volume is not for beginners - unless they want to pay a lot of tuition fees.

Thank you in advance for the feedback. Yes, I would definitely work with an architect and/or construction company. Right now, I am only interested in the very first calculation. So does it even make sense in times of increased construction costs and what is approximately the cost estimate.

I simply cannot imagine that you are allowed to build 700m2 of living space on 900m2.

If you include the normal parking spaces with about 1.5 per 10 residential units, plus the traffic routes, etc., it definitely won't work.

Then there are basement rooms that do not count as living space, on top of that.

Is there a [bb]?

But if all of this is possible, find a construction company as a partner. Negotiate with them that you keep 2 apartments for your own use and that they bear the risk and are allowed to sell the rest for themselves.

Well, you are allowed to build 3 floors, so with a factor of 0.4 after deducting 25% for walls, stairwell etc., I come to about 700 sqm of living space. Interesting suggestion! However, that would mean I would have to sell to the developer? A sale would be very unfavorable tax-wise as I do not want to enter commercial activity.