Construction on someone else's property with subsequent purchase

It would be important to us - if she cannot be persuaded otherwise - that the house to be built is our property

This is ONLY possible if the land belongs to you. So purchase before construction. It does not work otherwise. Land and building are inseparably connected. The bank always auctions the land (with whatever is on it) and not the house.

Wrong! It is not about a purchase contract, but about a notarized purchase offer. This is legally not harmful and no speculation tax is incurred (provided the 10 years are observed at the actual purchase or acceptance of the offer).

But that doesn't help, then the topic starter has no security at all. She needs an acceptance before construction can start...

Wrong! It is not about a purchase contract, but about a notarized purchase offer. This is legally not harmful and no speculation tax is due (provided that the 10 years are observed at the actual purchase or acceptance of the offer).

The purchase offer can only be one-sided (on the part of the buyer), whereby the purchase price can still be fixed now. Everything else has already been described above, would not withstand a closer examination by the tax office and the speculation tax would be due. I am not a tax or (heritable) lease expert. By chance, I have a very similar situation and have of course informed myself legally about why, how, and with what consequences. Note: I have a heritable building lease property with a low leasehold fee and a one-sided notarized contract (purchase offer). If it is accepted by the seller after 10 years, the previously agreed purchase price becomes due. If not, I continue to pay the leasehold fee (also no problem for me as it is cheaper than financing the property and 99 years is so long that a sale of the property is also possible without any problems).

I am not a tax advisor, but what about a building leasehold? You could build on it as leasehold tenants and the construction can also be financed this way, the seller receives sum X annually, monthly, whatever. The term of the leasehold should be as long as the financing lasts. This way you could pay the (partial) purchase price in installments and the leasehold contract should stipulate that the leasehold tenant has the right to buy the land after the term expires for sum X (e.g. your intended purchase price - paid ground rent + sum X so that the seller agrees). There are certainly other constructions with a leasehold contract.

But it is just a spontaneous idea, a tax/legal advisor should look at it carefully. Possibly a consultation with the bank is also necessary to see if they accept the term of the leasehold (they still evaluate this differently). It obviously costs a bit extra to draw up the contracts, but not excessively.

I would like to correct myself here once again: The ground lease interest should be as low as possible, since it also has to be taxed ;) Then increase the purchase amount at the end.

I am not a tax consultant, but what about a heritable building right?

What does the seller get out of it if he wants to sell? He has to put money into the heritable building right and then later sell the land. It all just costs money and doesn't really help.

The duration of the heritable building right should be as long as the financing runs.

That is not enough. The heritable building right must last longer, otherwise there will be problems with the lending. The congruence you mentioned would also be a deal-breaker for us. In the end, the only viable structure is: buy and get the speculation tax refunded. Everything else is (more expensive) nonsense. We're talking about "peanuts" with the land prices.