Temporally separated construction of a semi-detached house (as a condominium owners' association) on an undivided plot

Total costs would be about 550k € acceptable - excl. kitchen and any new furniture. So that leaves 300k € for the semi-detached house. That sounds like little at first, which is why we want to do a lot ourselves.

My own home would be worth it to me. At these prices, we will hardly be able to afford anything of our own otherwise. The price increase is wiping out my savings alone.

Do you have any number for that?

If you wanted to build a single-family house, then you could pull out of the BT thing. With a partial development, there are other problems, namely the prerequisites. I assume that it is a recently completed new development area, where this plot is still available. The seller is the city/municipality?! The BT has already built some houses there, regardless of how or in what capacity. Since "people" know each other, there is now this option to build with them as well. If you decided to do that (1) (why not, it shouldn’t be a tied sale with purchase in 2025, building contract in 2026), he would make you one or two proposals (single-family house, semi-detached house, two-family house), plan with you and then build the desired semi-detached house. Beforehand, you would have bought the ideal half and the BT/contractor possibly the other half, in order to then sell it together. Or the agreement also applies to the second, first buy the plot, then the semi-detached house, but probably as a tied sale. Anyway, that shouldn’t be the topic here, just explaining a bit. What you can do is (1). Or you can (2) buy the whole plot yourself. Find a building partner for the second half, then together find a general contractor who will build you your semi-detached house. Possibly you end up again with the mentioned BT/contractor, could be. But that definitely means + 1 year, if not more. Buying only an ideal half is legally possible, but for all matters the condominium ownership law (WEG) applies, so the signature of both owners is required. You don’t really believe that the city wants to constantly be a suffering “plot” partner making decisions with you when they want to get rid of the plot. In theory, they then permanently sit on an ideal half while you plan half a house. That’s not how you sell in the construction business. And you don’t want that either. I have no problems with WEG or ideal division. But you have to be able to communicate as partners who want that and are equal. However, I wonder why you reject the BT. He doesn’t seem to be bankrupt, has done everything right (otherwise he wouldn’t still be in business), and on the whole there shouldn’t be any major construction defects.

You can't provide labor services worth 100,000€. You can manage 20,000€ together – a one-year vacation. Alone you are on the construction site every weekend and ruin your back. Your family gets nothing from you anymore, and all for a home for the family that might lose stability because of it.

That's how it is and always will be: nowadays you don’t get a house of about 130 sqm for 300,000€, especially if you still have to spend 30-50,000€ of that on additional construction costs. Even if you can save with own work, materials cost money. Also, your brother-in-law, if he is still involved, doesn’t get anything for free and has to work too. And if so, I advise an expansion house, but please not a pharmacist like Schwörerhaus and co, I expect you, who have been searching for two years, to have more knowledge about house construction. I think if you have a good understanding of prices as well as condition or costs of renovations, then you can eventually say yes blindly before you’ve seen the property in person. There are people who can name you the construction blunders of every year of the last 40. And they only started counting from when asbestos was banned.

By the way, if you have further questions about building on the same property, it is recommended that you continue and use the existing old thread, simply with words like, “it continues,” “there is new information,” or similar.