Building a house without equity - is that possible?

You are in your early 20s and married. Therefore, I assume that sooner or later you want to have children. If we assume that you pay off 1500 euros monthly for 20 years, at the end of the fixed interest period with a 450k loan and 2.2% interest rate, you will still have about 250k remaining debt. So at a time with absolute low interest rates, in 20 years you will not even be able to repay half of your debt and will have to give up a lot just to get by. You probably will never be able to offer your children anything either; every school trip will leave a big hole in your household budget. I actually only see a chance for the plan if you save up some equity for a few more years and you are lucky that there will be a negative interest rate then. I would definitely wait/speculate for this moment, and if it does not come, you will have already saved some equity. I don’t think it would be fair to your future children if you stretch everything so thin. When children are the most expensive, you will probably also already have your first house renovation. What do you want to offer them then? For example, we save the entire child benefit for our child every month because we can and do not really have to restrict ourselves. It will surely be needed one day (school trips/driving license/car/studies...). By the way, we have a very similar income, although we are significantly older, pay off only about 1200 euros, and will have finished paying off by about age 50. The main reason is equity over 30%, resulting in a better interest rate and not even half of your loan.

Money for vacation is not listed because one never takes a vacation. And it should stay that way until retirement. No hobbies, no cinema, no visits to restaurants or city festivals. What happens in case of a car repair or a broken washing machine? And don't you need books for studying? A scary thought how some plan their lives. How children could even remotely have a place there (who then are forced to never go on vacation or have hobbies, sports clubs, etc. either because the financing runs until they move out) is really beyond me. One can only hope that at least Christmas presents from Grandma and Grandpa are in there. Yes, when you’re young you are sometimes naive and don’t yet know what life has to offer, but I wasn’t that naive back then either.

Oh dear, now I really feel quite old...

Money for vacation is not listed because one never takes a vacation. And that is supposed to stay that way until retirement. No hobbies, no cinema, no visits to restaurants or town festivals. What happens in case of car repairs or a broken washing machine? And don't you need books for university studies? Horrible idea how some plan their lives. How children are supposed to have even a remote place in that (who then inevitably also never get to go on vacation or have hobbies, sports club, etc. because the financing runs until they move out) is really beyond me. One can only hope that at least Christmas presents from grandma and grandpa are included. Yes, when you are young you are sometimes naive and don’t yet know what life has to offer, but I wasn’t that naive even back then.

Oh dear, now I really feel so old...

youth has different ideals

It's nice that you already think about your (domestic) future at that age. Why don’t you also do that with regard to the children you want: You Even if they are only wanted in a few years, think about them today as well. Surely you want to treat your offspring to something eventually, don’t you? With the current situation, there will be nothing more than a lukewarm handshake per month left. And that for the next 10+ years, because if you buy now, you will hardly be able to save anything away in the next few years. My heart would break if my children had to suffer because of a wrong decision I made at 19.

Save some more in the coming years, at your age a house won’t run away from you.

The 3800 are the starting salaries at 19 and 20 years old respectively. Assuming a positive development in the German automotive industry(!), these should rise quickly.

What my two cents or compromise proposal would be:

save the desired rate aside for at least 1 year and honestly see if that works. No exceptions! And then you can use this as a down payment for a plot of land – but please one without a building obligation. Then pay it off with the rate and calmly deal with the topic of building, but start at the earliest after 4 or 5 years. Until then you are flexible and already saving in real terms. Such a plot is sold faster and also without many emotions than a house.

By then you should also know if you really want to build and how much money it is worth to you, and also show an increase in salary. And the bank sees the land as equity and that you are willing and able to pay this rate. You would then be around 25; at this age, my parents' generation often already built in the 70s and 80s, they were not as hedonistically inclined as many younger people today who want to live out and realize themselves into their 30s and then only think of children and house at 40. That of course also has to do with the professional situation (long studies, chain contracts, temporary work) but besides that it is also a matter of attitude. And in both respects I already see you capable if you can wait at least another 5 years.

The only disadvantage would be that with the purchase of the land you are tied to the financing bank for the loan for the house construction as long as it has not yet been paid off.

You probably will never be able to offer your children anything either, every school trip will tear a big hole in your household budget.

I wouldn't find it okay towards your future children if you always live so close to the edge.