Construction financing despite EU pension

So the whole thing would be recalculated when she returns from parental leave, starts earning a salary again, and signs. That would probably be the only option

Then everything will be fine. The only problem is that she will have debt, and you the assets...

I wouldn’t do that if I were your partner unless she becomes the owner. Otherwise, ask the local bank.

We would get married anyway this year and the renovation ultimately benefits both of us since she also lives off the income. She would only be listed as a second borrower, I would have to pay the installments because with her 800 euro salary she wouldn't be able to cover the installments anyway. The parental leave lasts another year anyway, until then we have to see. Thanks anyway

Well, you are going to get married this year and the woman is going back to work. When will that be? Can't you just wait until then?
Have you been to local banks or to brokers?

There is no "second borrower," but you are both liable 100% for the full amount. Will the woman also receive ownership in the land register in addition to liability for the loan debts?

Parental leave still lasts two more years and I actually wanted to start this year. I inquired at Raiffeisenbank, Sparkasse, and Postbank, all without success or only on the condition that my pension is permanent or my partner joins after her parental leave. She will not be entered in the land register, as she is the sole owner of her childhood home.

And would your wife's 800€ be enough to get a 100k loan? I can't judge, but it still seems too tight to me. What needs to be renovated? 100k is not exactly little with your income. What are the chances that one of you could earn more again? Can't your wife go back to work earlier? My personal opinion is that you are overindebting yourselves. The children are getting older and with them their wishes and thus your expenses. And what will happen when this pension runs out? Instead of your parents, I would also never have the usufructuary right removed. If you can't service the loan, they will lose their hard-earned home. And if you argue, possibly even that. You just can't impose such a risk on your parents... (And I am really grateful when my parents support me, but really only as far as it continues to be good for them themselves)