Semi-detached house, we have no basement, neighbor has a basement

Wow, first of all, many thanks for the many good answers in such a short time.

We learned from the municipality today that we will only be given the neighbors' names once both notary appointments have been definitively confirmed. That means we have to wait until then. Of course, we will talk to the neighbor beforehand to see what their plans look like. Maybe we can even agree on a joint developer. (Does this actually make it cheaper for both?)

Yes, we would basically like to build a basement, but since the plot of land here in the Munich area costs more than the house, (probably) unfortunately no budget remains for a basement (about 70,000 including everything).

We have already inquired with some developers about the costs. We were told that the cutting back (is that the right word?) of our plot if the neighbor builds a basement would cost in the range of 8,000 - 10,000 euros. If I understand the previous comments correctly, we have to bear these costs if the neighbor's basement is already there, meaning he builds before us or at the same time as us. Is that correct?

Is it also specified which of your neighbors (left or right) would be your semi-detached partner?

Are only semi-detached houses allowed or also detached houses?

Only semi-detached houses are allowed on this plot. Our half would be the right side. It is a plot that the municipality itself is selling.

Is it just your budget or is the plot (e.g., because of more than half a meter slope in the building window) rather "pro basement"?

The plot is perfectly level except for a minimal slope (barely visible).

Write to the municipality that you waive data protection and ask that your address be given to the others. There are things that must be agreed upon in advance, namely with the "other half." Agree on a general contractor – I don’t understand the municipality at all here: selling a contiguous property separately. That only causes trouble.

Regards, Yvonne

(Does this actually make it cheaper for both parties?)

Yes, cheaper in the sense of being more efficient and having a better construction process. And you also save money (spreading fixed costs). How much of that benefits you is not so easy to say.

I would definitely try to have the duplex built as _one_ construction project. Each person can still have their own floor plan, their own interior fittings, and their own building services.

Does anyone here have practical experience with this? Specifically the arrangement of two builders, one general contractor, one duplex? How is this structured contractually? Often a developer builds a duplex and then sells the halves separately.

Oh, the discussion again ...

No, both semi-detached houses do not have to be built by the same construction company and there will still be no trouble .... Always these old wives' tales.

: I rather believe that the city does not disclose the names of the other buyers so that people don’t reconsider and drop out at short notice. This has nothing to do with data protection.

Write to the municipality that you waive data protection and ask that your address be given to the others. There are things that must be discussed in advance, namely with the "other half".

I have now written to the municipality again that we agree to an early data transfer.

: I rather believe that the city does not disclose the names of the other buyers so that one does not change their mind and back out at the last minute. That has nothing to do with data protection.

Yes, I suspect that too. They are surely afraid that buyers will back out if you don’t get along well with the neighbor...

No, both semi-detached houses do not have to be built by the same construction company and there still won’t be any trouble

I haven’t heard of any construction project that didn’t have trouble. Why should it be a good idea to add extra complexity? Of course it can work out well, you just have to take a little more care than usual (interface coordination). You just need two(!) good site managers, most are glad if they’ve found even one.

I rather think the city doesn’t release the names of the other buyers so that people don’t reconsider and back out at the last minute. This has nothing to do with data protection.

Of course it is a matter of data protection whether and how personal data is passed on to third parties. And if a buyer backs out, you just take the next one nowadays.