Construction of a detached single-family house on two semi-detached halves

Good morning.

We have found two nice adjacent plots. The city (in NRW) has issued a preliminary decision for the construction of a semi-detached house on these plots. (Sale by private party)

According to §34 of the Building Code, the development must correspond to the neighboring development. There are mainly detached single-family houses here.

We are considering the construction of a detached single-family house. Has anyone had experience with how generous or strict cities are with deviating building requests?

How should we proceed in this matter to legally secure the possible construction of a detached single-family house on these plots?

How should we proceed in this matter to legally possibly build a detached single-family house on these plots?

It hardly gets easier: acquire both plots and notify the land registry office that you want to merge them into one plot. I see the preliminary building permit as applicable to a single-family house located in the building plot of the semi-detached house. A semi-detached house is nothing more than a detached vertical two-family house with a property boundary under the dividing wall between the apartments.