Financing single-family house with granny flat for parents

How can I legally establish an intention to make a profit if I offer a new building at 50% of the local customary rent and obviously make a loss?

If you only ever incur losses, then not at all. It's a question of financing, at 1% much easier than now with four times that. My tax office is satisfied that I show a profit every three to four years over the last 20 years (condominium of my mother) – but I am also at 70% and not 50% rent.

The goodwill of your tax officer has nothing to do with being "legally sound." Anyone who ends up with the wrong one will have serious problems with this model.

The goodwill of your tax officer has nothing to do with being "legally sound."

Due to moves, there are now 5-10 different officials in four cities. Therefore, it is not goodwill, but a fundamental intention to generate profit. If advertising costs come from maintenance reserves due to renovations / refurbishments / repairs, I cannot influence that – my intention to generate profit exists without special factors. Everything can be managed quite well and the intention to generate profit can also be proven at the beginning of the rental period. A nice Excel spreadsheet helps to provide evidence. The intention to generate profit is calculated not over a few years, but over the total period (that was once 30 years if I still remember correctly). Due to progressive repayments, the situation looks quite different later on regarding advertising costs. Furthermore, the landlord can apply a flat-rate surcharge of 10% on the income side over the term and, conversely, apply a 10% deduction on the advertising cost side. You either have to deal with the subject yourself or spend money to go to a tax advisor. And if I want to be on the safe side, I take a 75% rental estimate. Because then you don’t even have to discuss it anymore, as this rental estimate is considered sufficient for the intention to generate profit. "Legally sound" works, but with low interest rates (although that topic is now over) and at the same time only 50% rent, it is difficult to calculate.

Yes, I see it all the same. But the OP wrote in his opening post that he wants to make the loan part for the granny flat interest-only at first and put as high a repayment as possible only into the loan for the private rooms and from the outset calculates a loss of 150 euros for the granny flat, also as part of the financing. And you just shouldn’t do that.

Just forget about such loans for yourselves. Even the 800k for €3,650 is fantasy. That would be a 5.4% annuity. So a repayment of at most 1.4% and on top of that a huge financing gap. Find a project you can actually manage and bury these dreams. Sounds harsh, but it is the only sensible thing.

I honestly don't understand the thread either. The land and construction costs might still somehow be feasible at the moment (already not in Bavaria), but by the time you have a plot, that won't be enough anymore. The planned loan is large, although of course we don't know the income. The repayment with almost 4% interest is quite low though. So up to this point, it might still somehow work, but it would already give me major concerns. And then comes the joke that despite this! there is still a financing gap of 450k. If not everyone can expect 200k from their parents, it's pretty unrealistic to close this gap.