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

Please read. He has already talked to the office. Semi-detached house is allowed there.

Yes, semi-detached houseH is definitely allowed there. However, an entire duplex is still very questionable. If the municipality had wanted that, they would have divided the plots in the middle again. Possibly still possible, provided a very suitable division of the plot as well as exceptionally high site coverage ratio/floor area ratio.

provided an exceptionally high floor area ratio/floor space index is assumed.

It is about 557 sqm building land, which should be good for 300 sqm living space. That would require a floor space index of 0.6. For a two-and-a-half-story building (i.e., the type "two end-row houses") this would require about 150 sqm plot area, for a one-and-a-half-story building (i.e., the type "two 'detached' single-family houses") about 250 sqm plot area. I do not yet consider the former exceptional with a plot ratio of 0.3, the latter would require a plot ratio of 0.5 and would already be clearly exceptional; and if the plot is not intended for this type of development (with a whole instead of half a semi-detached house per plot), very unusual.

There have also been development plans in recent times that more frequently require minimum areas. For example, with 300 sqm, this plot would be too small to split. Anyone who bought it would then have to leave their buddy out and therefore pay for it alone.

In my view, the homework for the OP is quite clear: thoroughly clarify the framework conditions of the development plan, and urge the seller to split the plot and only then to sell to both builders individually.

To be honest, I expect that the ideas of the builders and the community will not come together here. If I were the community, I would take the next applicant on the list. If I were the OP, my (unfortunately more likely) worst case would be to be able to develop the plot with only one (single) house. But then the budget will probably say "no".

Hello everyone..

Thank you very much for the numerous replies. I had a late shift, can only respond now. I find it unfortunate that I am being called a "not to be taken seriously person" here. Sorry, I am simply a layperson in this field, have never built or anything like that. The problem is actually not whether I can build a semi-detached house together with my buddy or not. The following is allowed to be built: single-family house and a semi-detached house. Even a row house is possible. The floor area ratio is 0.4, two full floors are permitted. The problem is that I cannot simply sell the property further. The property was granted to me and not also to a second person. Apparently, this cannot be easily changed afterwards either. I really did not know that. And yes, I have to make a decision by Friday that will change my life. I did not choose this. Now my buddy has to submit a financing confirmation and his personal details by Friday. Then it will be decided in a council meeting on 03/20/18 whether the property will still be given to two people, that is my buddy and me. If not, I must still inform by Friday whether I want to buy the property also possibly alone. My cousin suggested the following, in case it doesn’t work out for two. I should buy the property anyway (I really want to, because it is, among other things, in a very great location.) We will build a two-story house, make the apartment downstairs ready to move in and leave the apartment upstairs in a shell state and complete it slowly as soon as finances allow. He had an architect with him. He told him the following: The semi-detached house will be more expensive for me. A single-family house as described above is cheaper than a semi-detached house. So of course the condition is that the community allows the property to be sold to two people. I will talk to my cousin tomorrow and then make a decision on Thursday. Hope I have answered all questions. Help from mom means that she will also live in the house. Only the two of us are left. She also still works and will support me financially as well. That was what was meant

And yes, I have to make a decision by Friday that will change my life. I didn't choose it.

Who else? Were you forced? Or did you wake up one day and think, I'll apply for a piece of land because it's currently being offered and now you're surprised that it's actually getting serious? Either way, now it's time and you haven't made any considerations so far about how this could work and you make all decisions in 3 days. Hats off! I have one more suggestion: marry your boyfriend, then all your problems are off the table. No, seriously. If the bank cooperates and the land is the right one, buy it. I would rather plan a small single-family house than with a boyfriend.

I have decided with my wife to buy an old building in two weeks. So: why not? Sometimes you have to seize opportunities.

If it is your dream property: definitely buy it.
You have the family connections to build very cheaply. Use them.
If the bank plays along, why not? If it doesn't work out, you can sell and pay your tuition fee.

I am optimistic and hope it works out with your buddy.

I also don't think the whole thing is really well thought out yet. There are still too many ifs for me. I myself also don't see how a duplex can be reasonably accommodated on 566m2. Your idea of the two-family house is also not quite thought through yet. You probably wouldn't have a closed, fully insulated building envelope. That would be very unfortunate energetically. In addition, all financial matters would have to be settled beforehand, since the shell construction, roof, insulation, windows, etc. would have to be built directly. Either you present that to your cousin upfront or he would have to invest money immediately.

Personally, I would also consider whether a small single-family house without a basement might be the better option for you alone. I think the house might even be almost cost-neutral, so financially it might fit.

On the other hand, I would also reconsider whether it actually makes sense to build as a single person. Of course, you can do that, but you are planning the house now for yourself, or for you and your mom. Whether that then fits for you and your family, you don't even know. In addition, your income is not high enough for you to simply pay it off on the side. With a loan amount of 280,000€, you will probably be paying around 1500€ per month including incidental costs. Can you manage with 1000€ for the rest including car, insurance, etc.?