How much does a semi-detached house cost? Is it much cheaper than a single-family house?

If you are allowed to build a semi-detached house on the property, a small house should be possible with your own work

But with a basement, it will be tight, won't it?

for 350K you get an approximately 180 sqm single-family house without a basement with medium equipment in Bavaria turnkey...

I would say a basement would cost a maximum of 50K....since your house is smaller and you can share many costs, I think it should be possible with a bit of own labor or individual contracting

That will be tight, but it could work. It depends on what kind of equipment you want and how much personal contribution you can make....

No one can really tell you exactly, since no one knows what kind of floors, windows, bathroom equipment, etc. you want. It's simply dependent on many factors. But as I said, I believe it can work!

It's going to be tight with a basement, right?

A basement is probably not going to work. It depends on the plot and what the OP wants to contribute in terms of personal effort.

Hello everyone,

thanks for the numerous responses. So the plan is as follows: We would hand over the shell construction to a construction company and arrange the rest ourselves. My cousin has built twice himself. He has a roofer, an electrician, etc. So we have everything. It will not be handed over completely turnkey.

One more thing: The city is causing problems. I applied for the plot alone. They sold it to me. Reselling, that is sharing the land price, notary, and acquisition tax, is apparently only possible to a limited extent. They want a financing confirmation from the friend by Friday and it still has to be decided by the municipal council. But the friend only has an appointment at the bank on Tuesday.
One question, assuming I buy the plot myself, what I do after the purchase is none of the city’s business, right? Then you would just have to pay the notary and acquisition tax again?

It probably won't be that simple. The critical point is first the development plan. It must initially allow for a semi-detached house, and the floor area ratio / plot ratio must also be exceptionally high. Setback areas must be observed, etc. The plot still needs to be divided, so the building authority must cooperate first. Financially, however, as long as the legal aspects are clarified, it should be feasible. If you really know many trades and can do a lot yourself, it’s also possible with a basement.