Land use for semi-detached houses or halves of semi-detached houses

Hello dear builders and construction experts,

I am new here and still feel like I am in the early research phase on the topic of building. You can already find answers to many questions on the internet, but often not specific enough for your own case. Therefore, I would like to use this forum to possibly get some input that can help me with my questions.

The framework conditions

There is a developed (and currently uninhabited) plot from the family, which is to be used for a new building. The plot will be transferred to my wife and her sister-in-law in the coming weeks. The existing property from the 1930s cannot be renovated for less than 75% of the cost of a new building. Also, the size, layout, and location on the plot do not fit for a possible conversion into a kind of semi-detached house. Currently, we are pursuing the plan to demolish the house and build a semi-detached house or two semi-detached halves on the plot or plots. For this purpose, the plot is to be divided into two equal halves. This leads to the first question...

Questions

[*] Currently, we prefer a real division of the plot (instead of an ideal division) so that there is a clear separation and no dependencies arise and, so to speak, no "agreement obligation" when it comes to the house. This can be difficult with an even number of parties. (We are thinking more about the future, in case one half needs to be sold.) Currently, there is only one house connection. If the plot is divided in reality and two semi-detached halves are built, are you then forced to create another connection to sewage, water supply, electricity distributor, telephone, etc.? (I have read that one may possibly manage with only one house connection and could arrange something like this via an easement, but with disadvantages for the servient party.)
[*] Has anyone of you already had such a case or something similar with the same questions?
[*] Is our preference for a real division well argued, or are the disadvantages of an ideal division not that great?
[*] We have already obtained a few offers for the house (so far only prefabricated house providers – solid house, developers, etc. to follow). It has become apparent that building a semi-detached house can be somewhat cheaper than building two halves. Here, property formation would then be pursued. In this case, it would actually be better to divide the plot ideally since you would then create a community of owners, right? (Regardless of the fact that we currently do not favor this.)

I look forward to answers and already sincerely thank you for them.

Markus

It has been shown that building a semi-detached house can be somewhat cheaper than building two separate halves.

What do you mean by that? - the house itself doesn't notice whether there's a property boundary between its halves. The difference would therefore architecturally be at best that between a party wall and two "exterior walls" (i.e., a simple or a double partition wall) and whether both halves are fully equipped or if one of the two has a house connection room almost in "slave mode." It would be best if you also showed a cadastral extract of the property, so one can visually imagine its divisibility. Would both halves have direct access to the street?

If the property is divided physically and two semi-detached houses are built, are you then forced to create another connection to the sewer system, water supply, electricity distribution, telephone, etc.?

This must be considered separately for each point. Sewer connection: Each municipality regulates this individually in a statute. In our area, each property must generally have its own connection. However, upon request, several properties can share a connection line. A prerequisite for this is the securing in the land register. Water: §43 Building Code NRW (2) Each apartment must have its own water meter. This does not apply in the case of changes of use if the requirement according to sentence 1 can only be met with disproportionate additional effort. The technical implementation must then be coordinated with the utility company. For electricity and telephone, in my opinion, there is no obligation to connect. If the neighbor allows it, you can use their router, as well as their electricity connection.

(however with disadvantages for the servient party)

The disadvantage can be compensated with money. However, I question the purpose of physical division if you then make yourselves dependent on each other again in such fundamental matters.

Is our preference for a physical division well argued or are the disadvantages of a notional division not that great?

I also prefer the physical division because it means one more commission . Joking aside: It is a personal weighing of costs and benefits. I know owners of condominiums who report no problems at all and others where scraps fly at every owners' meeting. If there are no legal objections, I recommend physical division as the greatest possible independence means less potential for conflict.

It has been shown that building a duplex can be somewhat cheaper than building two separate halves.

Perhaps the manufacturer also gives a bonus here for having only "one contractual partner" and therefore receiving change requests from only one source. Is the cheaper price still given if both halves are not exactly mirrored, but individual wishes are taken into account?

If you want a duplex with different halves (size, room layout) that is seen as a unit from the outside, you are probably better off with a solid construction general contractor and architects for planning beforehand than with a prefabricated house manufacturer.

Since a declaration of division must be drawn up by a notary even in the case of a notional division, the additional effort for actual division is not that great—mainly the surveying costs.

I could imagine that with a semi-detached house, a few things might be implemented more cheaply if shared. The heating comes to mind spontaneously. Of course, this also carries potential for conflict...

that with a semi-detached house a few things can be implemented more cheaply if shared. Heating comes to mind spontaneously.

I would have said that a few years ago as well, because the efficiency of today's technology increasingly calls small systems for each residential unit into question. But today, the fact that the range of technologies is becoming more diverse also plays a role. I wonder if the wives of Cain and Abel always have the same preferences?