Feasibility financing new construction (land + semi-detached house or semi-detached half)

You write "roughly" 320k. Two years ago, all prefab house providers here also said that our project would definitely be possible under 400k (the plan was completely finished then). But the two actual offers were 450k.

And I can hardly imagine that a basement makes much difference without a slope. The offers for our basement were 80k without earthworks. I don't know what the foundation slab would have cost, but hopefully 40-50k less...

Please always remember that on the other side are sellers. They do not always tell the truth.

If you want to go through with it, then absolutely without any extras. NO basement, no finished attic, laminate flooring, .... But I think as soon as the real costs come in the form of offers, the topic will be over anyway. At least if you make an honest calculation including ancillary construction costs.

Never. 2000 euros at 5(!!!!) for all other costs...
We have about 4k left after the installment for the three of us, and I'm worried that we will have to severely restrict ourselves in the future

But those are luxury problems you have. The average family in BW probably doesn't have much more than 2k left per month after rent.

You write "roughly" 320k. Two years ago, all prefabricated house providers told us that our project was definitely possible under 400k (the plan was completely finished then). But the two actual offers were then 450k. And I can hardly imagine that a basement makes much difference without a slope. The offers for our basement were 80k without earthworks. I don’t know what the concrete slab would have cost, but hopefully 40-50k less... Please always remember that on the other side are sellers. They don’t always tell the truth. If you want to go through with it, then absolutely without any extras. NO basement, no finished attic, laminate,... But I think as soon as the real costs come in the form of offers, the topic will be finished anyway. At least if you make an honest calculation including ancillary construction costs.

And when the ink is dry and the financing budget is exhausted, you’re screwed.... The negotiation pressure shifts, then the builder has the upper hand. And in the low-price sector, no one gives anything away. The price jumps in the trades/material also show this.

We had a few "soft items" in the construction as a buffer for things we couldn’t plan 100%. We could have still adjusted the variables if something unexpected happened. This included exterior facilities, paving work, kitchen, painting work, and possibly floor installation. We had all of these planned in the budget. However, if something unexpected had come up during the earthworks, we could have done some of it ourselves and would have had some budget left from the financing. Fortunately, that didn’t happen, but having an Excel sheet where I could exactly see which costs were already contractually fixed and how much capital we had left to shift to other trades always helped me mentally. In the worst case, of course, you end up sitting in your house surrounded by piles of dirt and a Euro pallet in front of the door. But with a small budget and a plot in such a good location, maybe that’s not the worst option?

But with a small budget and a plot in such a good location, that might not be the worst option?

The problem is that with shell houses there is practically no downward potential anymore. There are actually quite a few more things on the builder’s side than you think and are communicated, has already listed quite a few. Besides, the photovoltaic system is still missing from the list; from May, it is mandatory here in BW. A typical house will come out at around 5-6 kWp. That’s a few thousand more even though the project is already way too expensive. In short, the 320k for house and basement is definitely not enough to get it move-in ready (especially if you plan little own labor), the kitchen won’t be free but will incur additional costs, the ancillary construction costs are set way too low at 30k for a basement. With the planned rate, it is also completely unrealistic to pay for the exterior landscaping from the ongoing income after moving in.

Yes, that is of course true, 320k is probably far from reality. I also tried to read up on the topic to help, but on the Allkauf Haus website you really just read a lot of marketing nonsense (promotion here, special thing there, Joey Kelly this and that) – but few facts. It is prominently advertised "brand kitchen included," but how big is it? What does it cost extra if it doesn't fit? Such things are usually rip-offs or bait, so you have to read the fine print very carefully, and I simply cannot find any fine print on the website. It is unclear what is really included in your 320k.