ᐅ Enlarging the Living Room / Extending the Concrete Ceiling?

Hello everyone,

I recently moved into a relatively new house, built in 2016. The house is built with solid construction. The wall blocks are Gisoton blocks, 42cm (16.5 inches) thick. The house also has a full basement.

As usual, you only notice some of the less optimal aspects once you’re living in it. In my case, the living room is too small, so I would like to enlarge it. To do this, the basement below would probably also need to be expanded (at least in one direction), otherwise I would have to block up the basement windows. I did a quick sketch to show what that might look like:

As you can see, part of the garage would have to go. For the roof, I was thinking of a simple pitched roof that would connect to the main wall of the upper floor.

The question is whether it is even possible structurally to extend a concrete ceiling like this, or if that is generally not feasible? Maybe in our case it would also be possible to support the ceiling from below with a steel beam?

It would probably also be easier to enlarge the living room only toward the garage side rather than in two directions?

Overall, is it a bad idea to take something like this on, or is it doable?

I haven’t gone very far with my considerations yet, but before I approach an architect or structural engineer, I wanted to ask here first. Maybe there are some good suggestions as well. Of course, aside from the structural aspects, many other questions would have to be clarified (building permits / planning permissions, utilities, etc.).

Thanks, spyfromtheeast