Change of apartment layout plus extension

Hello everyone, we are currently facing the decision of whether to build an extension at my parents-in-law's place. So far, we have not involved an architect because we first want to consider how it could actually turn out.

I am attaching the current state of the apartment.

What is important:

-The main entrance and the stairwell must be used by both.
-Closed living area (currently everything is very open designed)
-2 children's rooms
-Bathroom, guest bathroom
-Bedroom
-Open living-dining area. Balcony and garden should be accessible from the living-dining area.
-Storage room

I have roughly created my own draft. This already results in quite a lot of hallway.

I would be very happy about further ideas.

Best regards Michaela

Sorry, but far too little information. What kind of house is this and on which floor are we? Apparently, an extension has already been added? Up to which floor? What are the walls made of? What does the development plan say about floor area ratio, number of residential units, parking spaces, etc.?
Discussing without any basics is completely pointless.

Thank you for your feedback. It is a two-family house. The apartment is located on the ground floor. There is a balcony at the front and at the back, where the extension would be, it is at ground level. Exactly, an extension has already been built. From the basement to the attic. However, we are only planning the extension on the ground floor. Unfortunately, I cannot say anything about the development plan at the moment. If a collection of ideas for the floor plan is absolutely necessary, I would find out about that.

First, one would have to check whether the floor area ratio can still legally justify an extension. Then look at the shape of the property, whether distances are maintained, etc. Then take the old floor plan and have a structural engineer assess the load-bearing walls. These should, if possible, remain or they must be replaced with great effort.

Vorne ist ein Balkon und nach hinten raus,

Where is "front" and "back" for you? Is front up or down? Or is front where a front door is? Then, of course, the routing of the lines from above must remain. Erasing them is not an option. In the existing floor plan, yellow is used for walls to be demolished and red for new walls. If everything is redrawn, the dimensions should match the original.

Regarding your drawing attempt: yes, something can be recognized. Even though you apparently drew a labyrinth. But honestly: one bed is half the size of the other, yet the dining table is bigger than the single bed. A children's room of 22 sqm, but a tiny sofa surrounded by walls. A wardrobe in front of a window? It all looks more than accidental. Have you ever dealt with renovation concepts? If you build new additions, to my knowledge the whole house should/must be brought up to current energy standards.

If you look at the existing structure, the space should actually be sufficient and suitable for 4 people.

I correct: of course you don't have to renovate the entire house. But an extension must meet the new energy standards. And it's worth checking everything.

Where is a "front" and a "back" for you?

Sorry, I am just very inexperienced. It’s probably annoying for you. The front is where the children's rooms are supposed to be.

About your drawing attempt: yes, you can recognize something. Even though you apparently drew a labyrinth. But honestly: one bed is half the size of the other, while the dining table is bigger than the single bed. A children’s room of 22 sqm, but a small sofa surrounded by walls. A wardrobe standing in front of a window? Everything looks more than accidental.

The labyrinth came about because the staircase has to be closed off so that we have an enclosed living space. The hallway to the kitchen/bedroom is certainly not absolutely necessary. That was just an idea at first so that you don’t have to go through the living room from the bedroom. And so it is somewhat visually separated. For example, if my husband has guests in the dining room and I have to go from the bedroom to the children’s room. Certainly not everything is perfect, but that’s why I’m here – to get ideas from you on how to design it differently. For now, I’m only concerned with the room layout and not with possible furniture arrangements.