Renovate existing house - More space for kitchen and bathroom - Ideas?

I suspect the bay window would be cheaper. :)

Really? You would have to change the entire exterior wall, so probably also on the upper floor? Well, with the first option you have to lay pipes for the kitchen, etc. I would have still thought that it would be cheaper. Can you roughly estimate how much something like that costs?

So pulling the lines shouldn’t be that much of a problem, since you also have the bathroom there. You should therefore be able to get water and wastewater there quite well. Otherwise, you can also check the basement and lay pipes there. The biggest problem would probably be the wastewater, but since the bathroom is next door, there has to be something there. Whether you can remove the wall without any problems remains to be clarified. But otherwise, you can also install a "static gate," for example, supports made of steel beams on each side and a corresponding beam on top to catch the load. In the end, that's no big deal! I think the bay window will be a different matter; in my opinion, that will be significantly more expensive. We also had something like that installed, and the whole thing cost us under €3000 including drywall. Of course, additional costs can still arise, e.g. floors, etc. But a bay window is, in my opinion, a different ballgame!

Maybe this is not noticeable at first glance, but in the 1st proposal all internal bathroom walls and the new bedroom wall are shifted, because otherwise no double bed would fit. This would also affect nearly all wall installations in the bathroom, tiles, electrical work. Plus the entire kitchen.

In contrast, an extension on the ground floor would presumably be relatively easy to connect. Windows open to the floor and possibly widen, base plate, small lean-to roof, electrical work, plastering, done. Well, avoid thermal bridges, connect gutter...

Ok, probably not much difference. ;)

I also played around a bit. I have no idea if this works structurally.

- Remove the wall to the kitchen and let the countertop run diagonally into the room. Thanks to the bay window, there is plenty of workspace on both sides. Unfortunately, the corner bench has to go.
- Replace the door and window with a sliding door element. With the sliding door, there is no door wing obstructing the table.
- The dining table size depends on what you need.
- I extended the wall by the fireplace into the room. This side is for the TV. On the other side of the wall, you can also put a cabinet or shelf. Then place the sofa in the corner. Unfortunately, the terrace door is in the way. Possibly move it if feasible, or otherwise just have a window and live with the sliding door for the terrace.

Whether the dining table and sofa fit can only be said once you have exact measurements.

I would, if the structural engineering allows it, open the kitchen wall to the dining area and separate the living room with a wall. Then there would still be space for a tall or fridge freezer - elegant two-liner or a U-shaped kitchen. I don't see many more nice options if you don't want to ruin the house. The house is what it is. I don't think the bathroom is too small either. Is there another one upstairs?

Otherwise: keep looking :)