Additional construction costs for new build on existing land

That is exactly the question. The property currently belongs to my parents. I cannot imagine that the state turns a blind eye because my parents "gift" me half of the property?!

If the property belongs to your parents, no real estate transfer tax is due upon purchase (§ 3 No. 6 Real Estate Transfer Tax Act: acquisition by a person who is related to the seller in a direct line). If you receive it as a gift, gift tax might be an issue, but the exemption amounts are usually sufficiently high.

Okay, those are interesting remarks, then we will reconsider the whole thing. Many thanks!