ᐅ Extension to a single-family house as a senior apartment, any ideas?

Hello. This is my first post, and it is very general. Yesterday, my wife and I were thinking about whether to have a one-story extension built onto our single-family house. Something like a small bungalow directly attached to the existing house wall. One of our children and their children would move into the larger house (for example, as tenants). We have no idea what options are available these days. Something simple and rectangular would be enough. Do you have any tips or websites where I can get ideas? A first Google search shows many results, but my internet experience tells me that the more specialized sites tend to be harder to find. Sigh, that’s how it is sometimes with spontaneous ideas.

This has less to do with insider websites and more with the fact that each of these projects is unique. It depends on the plot of land, the floor area ratio, parking regulations, the layout of the existing house, the space requirements for the extension, the specifications for the extension, and so on. Since you’re asking without providing much information, it will be difficult to give accurate answers.

kbt09 schrieb:

This has less to do with insider websites and more to do with the fact that every such project is an individual case. It depends on the plot, the floor area ratio, parking regulations, the layout of the existing house, the space requirements for the extension, the standards for the extension, and so on. Since you are asking without much information, getting precise answers will be difficult.

Thank you for the quick response. You are absolutely right; my post is very general. Unfortunately, I don’t know where to start. Should I first gather ideas and then check feasibility, or the other way around? The conditions are good. Our children/grandchildren live directly in the neighboring houses. There is excellent harmony, no issues with right of way or similar. On our property, there are about 250 m2 (2,690 sq ft) of free space. The extension should have approximately 90–100 m2 (970–1,076 sq ft) of living space. Small rooms are sufficient: bathroom without a bathtub, combined kitchen/living room, small bedroom, small office, storage room. So everything really is rather minimal and functional, as we are not home much. My question is more about the technical construction aspects. I haven’t looked into it much, but I keep coming across many buzzwords: prefab house, tiny house, and so on.

First, I would clarify whether you are even allowed to build an extension or any structure at all. If the building authority / planning permission office says no, then you don’t need to worry about the rest.

Frank-Ol schrieb:

Small rooms are sufficient:

That is understandable on one hand, but if it is intended to be a senior apartment, you should at least be able to move around comfortably with a walker. I have experienced myself how much space such a device actually requires.

Frank-Ol schrieb:

There is still about 250 m2 (2,690 sq ft) of free space on our plot.

That doesn’t tell you much. First, you need to check the zoning plan to see how much area you are allowed to cover with buildings (floor area ratio). Then, check if parking regulations require you to provide additional parking spaces. Is it permitted to build an additional residential unit? Would there be enough space for that? Next, sketch your plot or use the site plan and mark how much space you have available for the extension while maintaining required setback distances.
Please share the zoning plan and show your plot, for example with a screenshot from Google Maps.

Frank-Ol schrieb:

Small rooms are sufficient: bathroom without bathtub, combined kitchen/living room, small bedroom, small office, storage room.

"Small" is relative—please share your approximate planned square meters (square feet) for each of these rooms. Additional areas include technical rooms, entrance area, and hallway. Personal extra requirements such as a sauna, collections, two TV areas, grandchildren’s play area—we don’t yet know your wishes. A Google Maps image with the planned building area marked and a north arrow would help generate ideas.