Building housing on existing land ownership - ideas wanted

Hello everyone,

actually, I am not a big fan of building a house, as I also see higher living costs and inflexibility in a house. However, the former especially changes if you could build on existing spaces. This concerns a three-sided farmyard (residential house, barn, garage) with green space around it. Since the conceived possibilities are all "special solutions," I wanted to first get information about whether and with which option it makes sense to inquire more closely.

The wish would be for a single-story house as much as possible (because I like large rooms but don’t need 250m²) without a basement and space for two (so no children's rooms, etc.). However, it should be relatively modern and flooded with light, so somewhat higher costs for the windows need to be calculated.
The options all depend on the required building permit, which certainly varies from case to case, but maybe someone can already give an assessment.

Option 1: New house on adjacent meadow:
For personal use, you often see new houses on adjacent meadows (mostly from farms), although there is no zoning plan from the municipality in the area. The three-sided farmyard is not a hermit's house, but there is also no zoning plan. What are the chances that the municipality will allow new construction on the adjacent meadow (without "I know someone...")? In the past, another adjacent meadow was rezoned as building land. How high are the construction costs without the land but with development? Do you save a significant amount that way at all?

Option 2: Extension to existing building. Here too, it is of course unclear whether an extension is allowed. The disadvantage would be that the extension would have to be on the west side. So no southern windows (unless you make the extension with x meters distance from the existing building). The advantage is probably that, provided the connections are sufficiently dimensioned, no development is necessary(?).

Option 3: Conversion of the barn. This option would of course be the most beautiful or individual variant in terms of construction technology. But from what one reads, you have to reckon with higher costs than with a new build. However, the plot would be available, and new development might not be necessary. Then a huge part of the costs of a new build would already be saved?

Since I am a layperson, this is often wishful thinking and reality quickly catches up (building permit impossible / costs higher than new build + land). What information would be necessary for assessment? Which option would have a prospect of success?

Option 1: New house on adjoining meadow: For personal use, you often see new houses on adjoining meadows (mostly from farms), although there is no development plan from the municipality in the area. The three-sided farmyard is not a solitary house, but there is also no development plan. What are the chances that the municipality will allow new construction on the adjoining meadow (without "I know ...")? In the past, another adjoining meadow was already rezoned as building land. How high are the construction costs without land but with connection? Does one actually save a significant amount?

Option 2: Extension to existing building. Here too, it is of course unclear whether an extension is allowed. The disadvantage would be that the extension would have to be on the west side. So there are no southern windows (unless the extension is made with x meters distance from the existing building). The advantage is probably that, provided the connections are sufficiently dimensioned, no new infrastructure is necessary(?).

Option 3: Conversion of the barn. This option would, of course, be the nicest or most individual variant technically. But from what you read, you have to reckon with higher costs than for a new building. However, the land would be available, and new infrastructure might not be necessary. Then a huge part of the costs of a new building would already be eliminated, right?

Since I am a layperson, this is often wishful thinking and reality quickly catches up (building permit impossible / costs higher than new building + land). What information would be necessary for assessment? Which option would have a chance of success?

If you are located in an outlying area (which one can almost assume, since old farm), the probable answer to all options is: Not possible, as not approvable.

You get certainty with a conversation at the office or a building inquiry.

P.S. Why do you see saving potential in your options – costs will be identical? What is the difference in running costs? Do you now have greater flexibility?

...where exactly that was approved here in town two weeks ago: outdoor area, additional residential building next to the farm, passed by the municipal council.

...where exactly this was approved in the town two weeks ago: outdoor area, additional residential building next to a farm, approved by the municipal council.

Who is building there? Keyword "Altenteiler"

Read §35 of the Building Code, then you will know what is permitted and what is not. Is it also a §35 area or rather a §34? Have you already spoken with the building authority?

What about the other 2 parts of the courtyard buildings (except the barn)? Are they inhabited?

Who is building there? Keyword "Altenteiler"

Read §35 of the Building Code, then you'll know what is allowed and what is not. Is it also a §35 area or rather a §34? Have you already spoken with the building authority?

I'm not the OP ;)
Just wanted to say that there can be exceptions. In this specific case, I don't know the details, only that a new building on the meadow next to the farmstead was approved, it was called an "exception" in the report of the municipal council meeting...