Purchase or donation of the parental home for maximum support

I know there's some truth to the saying "you don't transplant an old tree," but wouldn't it be a serious consideration for both sides if you bought the house from your parents-in-law and they moved into a nice, age-appropriate rental apartment with that financial security? Then you could start renovating the house without any regard or restrictions, your parents-in-law wouldn't be exposed to months of reduced living quality due to noise and dirt, and you would have – as far as I can judge as a layperson – significantly fewer problems regarding the notarial and financial processing...

Expert for determining the market value (expensive)

Not necessary

Definitely split the plot and include half in the market value of the upper apartment (expensive and high effort for surveyors, land registry etc.)

For condominiums, the plot is not divided and does not need to be surveyed

Declaration of division

You can create it yourselves if necessary, there are even templates on the internet for that. The notary then only certifies it for a few euros.

Time required for these matters about 1 year

The above points can be done by yourself in 15 minutes / the land registry office can be ready in a few days or also months. But that doesn’t matter initially.

He finally advised against the undertaking.

I advise against your notary

According to your first assessment and my considerations, this should actually be possible overall with the declaration of division based on the planning and building permit and the division of the land register, right? Or am I wrong?

Yep

Register usufruct and that’s it.

If you officially buy from parents, I don’t know if taxes apply and whether these might be higher than the Baukindergeld.

Register usufruct and that's that.

Then the house is practically no longer financeable!

If you buy officially from your parents, I don't know if taxes apply and if these might be higher than the construction child benefit

In a direct line, buying from the parents is exempt from property transfer tax. Except if your wife becomes a co-owner, then property transfer tax applies to her share.

Good morning, my answer has no relevance from a building law perspective but: Parents-in-law become in need of care and require state assistance, consider the following scenarios: Gift: 525 Building Code impoverishment of the donor. The social welfare office demands gifts back within 10 years or denies benefits due to the claim. Right of residence: The social welfare office will calculate a fictitious rent and demand it from you. Usufruct: here too the social welfare office will calculate a fictitious rent and demand it. Moreover, usufruct is viewed ambiguously by various courts. With usufruct one bears the fruits and burdens of the property and there are opinions that no actual transfer has taken place with usufruct and the property still belongs to the parents. Certainly, in every constellation your investment would have to be considered, but only what you can prove. The mere registration of a land charge will not interest the social welfare office. My humble advice would be to buy the property and have the parents pay rent. Here, for example, a right of residence with rent payment should be unproblematic. However, this must be notarized. Information according to the current status. Or you buy only the upper apartment and renovate only that. Regards Shenja

Hello everyone! Thank you for your contributions, I would like to give a brief feedback: We will not expand the parental home, as it would only make sense for us if the house were transferred to us. The parents do not want that. Overall, the positions have now hardened to the point that we do not "come together." On the one hand, it's a pity, on the other hand, when one door closes, another always opens – Luckily, we have found a buildable plot.