So many things are going wrong with the planning here.
Actually, I didn't want to write about this again, but after some of the posts here, I feel I have to comment.
What exactly is going wrong???
My question was solely about whether financing with a relatively low monthly rate (about €1000) and high to very high special payments (at least €10k, probably €20-30k per year) is possible and feasible. The basic idea is to agree with the bank on both (monthly rate + special payment) as low as possible (based on 30 years), but then finish much earlier (around 15 - 20 years) due to the actual high amount of special repayments.
It’s not about the price of the house (I consider €300-320k for 150 sqm without a basement very realistic just for the house, that’s also shown by the offers not yet finally negotiated so far). Outdoor facilities, kitchen, etc., I can pay in cash from this year’s variable salary portion. This will probably come too late to count as equity for the financing.
It’s also not about the question of why only €65k equity is available.
It’s not about whether my wife has an income or not; she currently has €450 and it will never be less, even with a second child. Together with my fixed salary, it is currently more than sufficient for living.
So if it is indeed the case that the variable salary portion is completely ignored by banks and building societies, that’s okay, then I have to figure out another approach. Buying the land first would be one option. By the time I have to build, I should have accumulated another €100k in equity.
All other comments are really unnecessary.