Building a house on (partially) someone else's land

Hello community,
can you give me some suggestions regarding the following planning?

What impact does building a house have on a property that is equally owned by 3 parties (family members)? Regarding the property tax, the regulation "building on foreign land" partially applies, but how is this actually reflected in the property tax? Is it then significantly higher or is it just calculated separately? What else should be considered?

How does a house construction by me affect the ownership structure of the house?

Thank you in advance for the help

As long as you are one of the 3, it is not on foreign land. Property tax is no different, no matter how many people own it. It is charged once and must be paid by one of the 3, or by each 33%. Normally, a building plot always belongs to 2 (married) partners, so that is more the rule than the exception. Who owns the house is already more complicated, but normally the one who built and paid for it, although it is not that simple. Getting a separation aka "division" done works, the notary does that, but it is not exactly cheap. Construction financing also becomes problematic if people are listed in the land register who are not involved in the construction: they would still be liable and in case of doubt lose the property (their share).

1. How do you come to the conclusion that you will get a building permit without any regulation regarding overbuilding?

2. Otherwise, the Building Code § 94 applies, the building part belongs to the respective plot owner, since you probably realize yourself that a regulation could be difficult here, you fall back to point 1 again

Is it then significantly higher or is it just calculated separately?

Property tax is calculated for the land, has nothing to do with the owner. Joint and several liability.

How does building a house by me affect the ownership rights of the house?

There is no separation between land and house. Then the house belongs to all three together.

What effects does building a house on land that belongs equally to 3 parties (family members) have?

Endless stress if you no longer get along. Deal-breaker for me. In case of doubt, also stress with the bank, at least more effort, since all three owners are also required for the land charge.

There is no separation between the land and the house. All three together then belong to the house.

Why can't this be done through a completely normal declaration of division?

Why can't this be done through a normal declaration of division?

You need a declaration of division to split into condominium ownership. This is not the case here (at least, that's how I read it). For that, there would have to be at least two units on the "foreign" property. Then it works and the TE's house becomes independent condominium ownership, the land itself becomes quasi common property (e.g. with special usage rights for garage, driveway, garden, etc.). In my opinion, the person who builds the house should also own the land (regardless of whether as full ownership or in the form of a hereditary building right, which could also be done here).