ᐅ Plot for Construction Adjacent to Existing Building – "Single-Family House in Grandma’s Garden"

Hello housebuilding enthusiasts,

My wife and I are considering the possibility of building a house and are currently exploring our options. One suggestion came from my wife’s grandmother: "Build in my garden; there is plenty of space!" We would like to at least follow up on this idea by clarifying how feasible it is and what obstacles might arise. Since I have been reading this forum for some time, I would like to bring this question to the group:

How feasible is it to build an additional single-family house on the existing property, and what challenges do you see due to local conditions? (Topics such as the modalities of property subdivision / land division I would like to leave aside for now.)

Here are the basic conditions:

• The grandmother lives alone in a small house on the property with a double garage and a garden at the back. Her house should remain unchanged.
• The property is almost square, about 32m x 32m (about 1000 sq m / 0.25 acres)
• On the property: grandmother’s house is in the southwest corner, garage is southeast of center, garden/lawn is in the north and west
• Surroundings: low-traffic street to the south, terraced house with five units (and their gardens/terraces) to the east, single-family house with gardens to the north, multi-family house to the west (my parents-in-law’s house, 3 apartments/floors)
• In winter, the property has limited sunlight for several weeks due to a hill to the south casting a shadow
• We are in Baden-Württemberg, within town limits, with no specific development plan / zoning plan
• The desired house needs space for 2 adults, 2 children, and 2 home offices (she is a teacher, I work in IT and often from home)

To illustrate, here is the relevant excerpt from the land registry map with an aerial photo overlay (north is at the top):

In addition to the described conditions, there are the following two “wishes”:

• Preservation of the garden in the northern half of the property
• Retention of the double garage

As an interested layperson, and based on what I have read here about lighting conditions, orientation on the plot, etc., I consider #1 feasible by focusing the new building on the southeast part of the property. Regarding #2, I see a problem, however. To use the southeast area effectively for the new building, my understanding is that the garage would have to be removed. Or, conversely, if the garage stays, I only see a very narrow strip of land next to it on the right, and the problem that the garage would block sunlight from the southwest/west. Additionally, the garage would likely prevent a central subdivision of the property (vertically in the image).

Any lost storage/parking space would need to be compensated for at least partly.

How do you assess the described situation? I am grateful for any input and look forward to your feedback.

Best regards,
Sebastian

Have you already checked the legal aspects regarding the development plan, Section 34, etc.? What about the boundary construction of garages on the east side? Has a setback been recorded in the land register for Grandma's property there?

Draw the required minimum setbacks for houses on all sides. It will probably become clear quickly that the double garage in the middle of the property obstructs a practical building layout.

So, I basically see the only option for building there is to remove the double garage. But first and foremost, it needs to be clarified whether any further construction is possible at all, and if so, what is allowed. Potentially, the double garage could be integrated into the house, but at first glance, I don’t see a clean solution there.

In my opinion, the best approach would be to "sacrifice" the double garage, then divide the plot and build on the right part.

Maybe the double garage could be converted into a single garage, and the house could then be built directly attached to it. This would leave some space along the eastern property boundary.

ypg schrieb:

Have you already checked the legal aspects regarding the land-use plan, Section 34, etc.?

No, we have not yet obtained any official information.

ypg schrieb:

What about the boundary construction of the garages to the east? Has a setback been recorded in the land registry for Grandma’s property there?

Do you mean the garages behind the terraced house (light gray, far right in the picture)?
We are not aware of anything related to that.
I don’t fully understand the connection. How does the boundary construction to another property affect our considerations? The setbacks at the border with Grandma’s property are being observed.