Very bad and large and shapeless. Replanning tricky - tips

The property complies with the Energy Saving Ordinance after the renovation and is therefore quite well insulated and does not heat up as quickly as an old building.

Mh 2.5 m ceiling height with or without new floor construction

with new floor construction. As already mentioned, the children's rooms heat up due to the large windows, which should be avoided with sun protection... but then it would be dark in the room again, which is also not ideal.

Yes, where is the architect of this project?

The architect of this project is also struggling a lot with the planning.

Then not much light comes in from that side either.

Are you sure that is really the most economical solution?

Without changing much. Mini pantry, in which by the way no freezer fits, remove it, neither the kitchen nor the children's room has a bitten-off corner
Connect the WC with the storage room and make it a bit deeper as a small shower bathroom for the children.
Enlarge the technical room a bit, especially if house technology, storage, and washing machine are to go in there
Large bedroom with access from the hallway and not from the vestibule
Own parents' bathroom with access from the bedroom.

Not much light comes in there, but enough.
The pantry and the bitten-off corner of the children's room have their purpose; the support pillar is hidden in the wall. Connecting the bathroom with the storage room is no problem, but making it deeper --> next support pillar.... the problem is to create the planning so that the support pillars do not interfere, so ideally let them disappear somewhere in the wall.

only the expansion of the ground floor is planned, which is also large enough at 230m2.

That is what I mean by naive planning: concluding from the sufficient size of the ground floor alone that the rest can be disregarded.

For residential use, I initially see the following measures as necessary: first, clarification of the residential use permit, especially if all remnants of farming activity on this area are abandoned. Second, achieving the currently required thermal insulation standard: structurally, I have some doubts about tearing out the floor and laying a new, insulated slab deeper down. I rather see the floor being leveled to an even surface, insulated on top of that, and the room height then ending up at 2.30 m. Third, the apartment must still be thermally separated from the attic (i.e., insulation on the ceiling of the upper floor). And now comes my favorite cookbook phrase: "before that we have" (namely: buried the supply and disposal lines—and non-covered inlets are required on exterior walls).

Overall, I see this actual "bungalow set in a stable" as not being any cheaper by a jot than rebuilding a comparable area from scratch.

And this, even though less living space would suffice for the family: most square meters here are not used for a loft feeling; rather, for the phenomenon that even on a large area many narrow corners can occur.

Honestly: rent out the stable under the photovoltaic system as a cool location for mobile discos and build a 160 sqm house for less money.

It would be helpful to have a classic conversion plan where gray / yellow / red show existing, demolition, and new. Regarding the roof, I doubt you can just neglect it. Just to keep it watertight can cost as much as a modest house – not to mention that the ceiling between floors would need to be fully insulated. And its statics will also need to be proven when converting. Are you sure residential use is approved?

The roof can be neglected, one side was re-covered 8 years ago, the other side can be re-covered for 10-12,000. And yes, the ceilings will be fully insulated with 240mm. We must of course provide proof of static stability... and yes, residential use is approved; it is a so-called conversion to residential space, sealed with a red dot and a grant from the ELR program of 50,000....... therefore no demolition either, otherwise there would be no 50,000 and it would also cost a lot more, aside from the fact that it isn't possible due to the attached building.

The supports in the barn are the real problem, as they are actually immovable,

Exactly. What still holds these supports securely when the ground around them is being dug out?

the architect of this project is also having a very hard time with the planning.

I don't see anything resembling the hand of a professional there yet. Among other things, there would be the tricolor plan.