Feasibility of financing a single-family house approximately 150 m²

600,000€ already sounds extremely high for a normal 150 sqm house with land at a (somewhat) reasonable price and without a garage. But if the cost calculation from the architect comes to that, then we can't change it.

I am at a calculated 550k tutto completto for 130 sqm on a plot for 70k. Of course, not in Leipzig but in southern Germany, and self-performed work only outside the house, but with a carport instead of a garage, somewhat smaller, and with the price from over a year ago. By the time you have tendered the trades, it will also still take a few months. In that time, prices will rise a bit more. In this respect, I would be surprised if you come in under 550k with the plan.

I am at 130 sqm on a plot for 70k with a calculated total of 550k tutto completto. Sure, not in Leipzig but in southern Germany and own contributions only outside the house, but with a carport instead of a garage, a bit smaller and with the price from about a year ago. By the time you have the trades tendered, it will still take a few months. In the meantime, prices will rise a little bit more. Therefore, I would be surprised if you come out with the plan under 550k.

I also think that 350k might be tight. We are at 421k for a 132 sqm house, however including the foundation slab, earthworks and drainage. No own contributions. The contract is from summer 2021, according to the general contractor our house would be calculated at 470k today (which doesn't mean much, I would probably say the same as a general contractor). The price increase for our project alone from January 2021 to August 2021 was 20,000€.