Is it possible to build a house with little equity?

2200 is therefore not the net amount? How much is the net? Credit + additional costs should not exceed more than 1/3. With the reserves, I also don’t see it as too tight in the first years of a new building.

As said, if you were to list your income and expenses exactly once, the assessment of the financial situation would be somewhat easier.

What is included in the total sum of the house of 250,000 EUR (level of completion, basement or slab, earthworks, house connections, [Energieeinsparverordnung-Nachweis], sampling, soil test, sanitary objects, floor coverings, kitchen, garage or carport, outdoor facilities, cistern, type of heating, with or without [Kontrollierte-Wohnraumlüftung], etc.)? Most of the time, the offer prices only include a certain standard package and everything beyond that (such as different floors, etc.) costs extra, some house providers also list the earthworks as owner-performed work, so these are not included in the price and without soil analysis of your plot, the costs for the earthworks cannot yet be finally estimated.

Heinz von Heiden offered a complete package! All we then have to do is renovate and install the flooring... everything else is included in the price

thought my list was good?^^
The entire project costs 250K, everything you listed "Dindin" is included, just without renovated floors and walls in the house (but that's not the problem)
We have 2200 € net available, from which food still has to be paid
According to my calculation, after all deductions (loan (approx. 800 €), additional costs (400 € simply estimated), food) we would have 350 € left for free use
But since I can't estimate the additional costs and how much should be set aside for repairs, I’m unsure if that’s possible!

Overall we have a net income of 2800 € and the question is, is it crazy or possible to finance a house that costs about 250K?!

P.S. by additional costs I mean the monthly costs that come up to us, like trash, electricity, etc.)

Heinz von Heiden offered a complete package! what we only have to do then is renovate and do the flooring... everything else is included in the price

Without a soil report, Heinz von Heiden cannot give a final price yet. At most, it can be a rough estimate.
What about external facilities, sampling costs, incidental construction costs, etc.?
At what amount are these calculated?

I find €2800 net too little for house construction.

2800 € net and a 300k house (forget the 250k) insanity! You don't even need to calculate or think further. We haven't even started building yet and are already at 45k additional costs.

A case from my circle of acquaintances: Net: 3300 EUR, construction costs (all-in) 230k. After 2 years in the house, in private insolvency. It certainly doesn't have to go like that, and many mistakes were made.. The main cause, however, was additional costs for the outdoor area and a certain standard of living. Then two cars broke down and so on..

Addendum: You are missing at least 20% equity. That is the main problem. Add some more savings as a backup and it can work. We have saved 30% equity and an additional 50,000 EUR as an emergency reserve, which will not be touched.