What loan amount is realistic for house construction?

Why did you actually ask the question? You contradict every counterargument to your plan and you have actually already decided to go through with it.

40k is practically not equity. That goes towards the incidental building costs. The whole thing is completely unrealistic.. but still good luck

Now I have to laugh - so as long as I get the loan, it is doable - that totally contradicts itself, my dear.

I've been laughing at this thread for a long time. It's a farce. But I'll give you a tip. There are dozens of brokers or your house bank. Just go there and have them calculate the volume with your income. Then you can approach the "building according to budget" again here and compare prices.

What did you pay? Please break it down a bit.

Thanks + regards
Michael

I have a detailed Excel list with about 250 items, but I don’t want to publish it like that.
However, I created clusters.
For the shell including windows + roof, we spent about €90,000 (as mentioned: a lot of DIY work here too).
Info: monolithic with 36.5 cm Poroton, Schüco windows, Wienerberger roof tiles.

For the rest up to completion, another €150k (including sanitary and electrical completely done by ourselves).

In addition, there were €36k incidental costs, €16k outdoor facilities (also DIY), and about €20k for furniture and furnishings (including kitchen).

You are asking here in the forum because you are unsure. There are voices doubting the financing, but you don’t want to hear them. Do you just want confirmation here that everything is fine to calm yourself down? That won’t help you later. Then you will be sitting in the unfinished house, moving from room to room to make it livable.

Regarding the personal contributions: Don’t underestimate the costs and the time involved. Do you have helpers? What if, shortly before the interior work, for example, you have a knee injury and are out of commission? Can your girlfriend fully step in for you or your father?
Do you have the appropriate equipment and tools, or can you borrow them? That can become very expensive. It’s tricky to ask acquaintances how much their home renovation cost. Most only estimate roughly and far too optimistically afterwards. We just laid water and heating pipes in the floor of the new kitchen. You wouldn’t believe how many small parts “disappear” there. How often do you quickly drive to the hardware store to get just two more fittings, three branches, and some insulation and quickly end up spending 100.

I am definitely always very optimistic about all this—but if you don’t have money in reserve for emergencies, meaning that, for example, your parents can suddenly contribute 50,000, I would definitely plan a bit smaller and more cost-saving. Leave out everything that doesn’t have to be there for now. Even the garage.

I am currently in the "final stages" of completing 100m² - started with a shell (roof, walls, no windows). I have done relatively little work myself (drywall, floor insulation, and ceiling insulation). Although planned differently, I have now finally had the painting work done - I will still lay the floor myself and install the doors. As I said, for 100m², I have spent about €120k. This includes the interior finishing (windows, walls, interior plaster, repairing the facade, electrical, plumbing/heating, tiles, stairs, doors), utility connections, and a minimum of exterior work (splash protection, path to the front door, one step at the house and side entrance door, supporting the parking space, about €10k for that). It adds up, from quickly buying a bag of fill, disposing of construction waste, needing another drywall panel, a bag of mortar, more screws... house number, mailbox, doorbell... the list is endless. Small things, certainly, but in total... I have doubled my original budget for the floors. I find your expectations quite ambitious. Even with both your salaries, it will not be a walk in the park. I have the same income and significantly less credit. And it is borderline, as I also had to add funds. Fortunately, the bank was able to make me a reasonable offer...