Conversion from a single-family house to a two-family house - Assistance with room layout

Hello, we are considering converting our currently single-family house into a two-family house. More like a two-generation house. My parents will move into the ground floor and we into the upper floor.

Development plan/restrictions
Since the house is already standing, I think this point has been resolved.

Requirements of the builders
Style, roof shape, building type: gable roof, multi-generation house
Basement, floors: 1 basement room + garage in apt. 1, ground floor, upper floor, attic not developed
Number of persons, age: 2x mid 50s, 2x mid 30s
Space requirements on ground floor, upper floor
Office: family use or home office? Not needed
Overnight guests per year: rather rare, if so max. 2-3 on sofa bed
Open or closed architecture: rather open
Conservative or modern building style: modern
Open kitchen, kitchen island: open maybe yes. No kitchen island.
Number of dining seats: 4
Fireplace: yes
Music/stereo wall: no
Balcony, roof terrace: no
Garage, carport: no
Utility garden, greenhouse: no
Further wishes/special features/daily routine

House design
Who designed the plan: do-it-yourself by ourselves.
What do you particularly like? 2 identical children's rooms, walk-in closet not in the bedroom, fireplace
What do you not like? The entrance area on the ground floor. There should be a guest WC with urinal, possibly if possible a shared utility room, storage area for drinks and various foodstuffs
Price estimate according to architect/planner:
Personal price limit for the house, including equipment:
Preferred heating technology: existing oil heating

If you have to do without, which details/extensions
-can you do without: bathtub in the bathroom is not essential but better with
-can you not do without: fireplace, corner bench in dining area, walk-in closet

Now to the plan:
The round circles in the plan are the fireplaces. South side is the entrance side.

The existing stairs from ground floor to upper floor will be closed. On the ground floor it will be built as a shallow wall cabinet. On the upper floor as storage for vacuum cleaner etc.

My parents are happy with the new layout of apartment 1. Since the space is a bit too small for a separate utility room, both parties are okay with using a shared one.

Since there are partly small windows and they are arranged oddly, we do not force ourselves to keep them. So we would also intervene in the facade, which is necessary in any case because a large workshop door is currently installed at the entrance door.

The wall from bathroom/kitchen to living/dining area is not a load-bearing wall. Only the fireplace must remain standing. That is why we considered, if our layout remains, whether the kitchen - dining area wall could be removed completely.

Whether the stairs thing works out if we manage the entrance area on the ground floor, we also do not know; we are lacking ideas on how to get everything under one roof on the ground floor. A guest WC on the ground floor would be ideal for us since there is a neighboring building with a small party room; also, one can use the toilet when working outside and does not always have to go to the upper floor. The washing machine would then also come to the ground floor, with a laundry chute from upper floor to ground floor.

I think that is enough for now. We are currently not making further progress with our ideas and came across this forum searching for possibilities. Hopefully the plans are readable and understandable.

It is a bit tedious to have to open PDFs with Acrobat Reader and remember the text for the plans (wall cabinet? vacuum cleaner?) In an existing property, existing walls must be distinguished from new ones, as well as load-bearing walls from non-load-bearing ones. What is one supposed to say? I’ve already forgotten what I saw while writing - I saw a very long hallway... and a missing bedroom on the ground floor. In this respect, it would be helpful if you upload the pictures as JPGs and mark the changes in the plans in red... or something like that. Regards

For the assessment of many things, measurements such as wall lengths, parapet heights, etc. are missing. North arrow in the drawings, so that one does not have to laboriously search for an orientation in the text and then mentally apply it to the drawing ;)

What about the DG? Should it still be accessible? Wouldn't that be additional space?

The new staircase will probably not work like this; it is the main access for the upper floor apartment, and if the sofa is still supposed to be at a reasonably healthy distance from the TV wall, there is no space left to enter the room after the staircase. Corner sofa with leg lengths of 180x200 .. is that realistic?

The dressing room seems to me like a senselessly wasted over 8 sqm .. Parapet height of the window? Where do you want to put cabinets there? Likewise the bedroom .. how is the bed supposed to be positioned?

Bathroom with sliding door, I would seriously reconsider that.

They have, however, become really nice large children's rooms ;)

I think an architect will especially help here.

I made it as a JPG file. I forgot to mention one important detail. The two floor plans with dimensions are those of the house in its current condition. The other two are our design.

I marked the new walls and doors in red. How can I find out which wall is load-bearing and which is not? I still have the old building plans from the 60s in the cabinet, can you tell from those?

We have planned the attic to be accessible only via a pull-down staircase. Since the house once had an extension, the upper part on the plan is impossible to convert because it is one step higher than the lower part; for the rest, we would have to see what is possible and whether it is worthwhile in terms of space. So far, we have not planned that.

The staircase shown on the plan is just a suggestion; we don’t know if or how that should work and need help.

In the bedroom, we have no closet, only a dresser and the bed, and that works because it’s quite small and we cannot place a closet big enough for both of us with the bed. That’s why there is the dressing room. But we were thinking of an open closet option there and thought the space would be sufficient?

The sliding door in the bathroom is correct; we tend to prefer a regular door.

Thanks

Regards Gerry