Load-bearing wall thin and strong?

[Promiscuos Monkey]

I have not bought the plot yet, so the question might be a bit premature.
Anyway.
The "house" is located in Provence, France.
You can only get a building permit for 20 m2, but I hope for 2 floors, which would give 40 m2.
The problem:
When you're building something this small, every millimeter counts.
So it's essential to find a wall that insulates well, no more than 200 mm, preferably less.
It must be load-bearing for 2 floors and inorganic, I think.
Too many insects in Provence for me to dare to build with wooden studs.
Already with a 20 cm wall, I'm losing 40 cm of floor space.
All suggestions are welcome.
simple image

 

[Lutte]

A wall with some kind of insulated block would have been perfect together with a cast vault for the upper floor.

If it's difficult for you to find Swedish products, then concrete hollow blocks filled with, for example, styrofoam beads can work.

 

[Promiscuos Monkey]

Does a 20 cm insulation block really support? Like isoleca?
If so, the problem is solved.
Provided the insulating ability is sufficient.
I don’t really know what is required here.
I haven’t gotten that far yet.
Many people build with hollow cement only. Seems cold to me.
My current house here has a 20 cm reinforced concrete wall.
Very cold in the winter.
A lot of cold radiation.
Now has a "coat" of 120 mm polystyrene.
Very warm and comfortable house now, but too big for 2.

 

[Kallebo]

Doesn't help you, but I'm so curious; what kind of plot only allows a building area of 20 m2? Is it incredibly close to the sea or is it an extremely small plot squeezed in somewhere?

 

[Promiscuos Monkey]

Doesn't help you, but I'm so curious; what kind of plot only allows a building area of 20 m2? Is it incredibly close to the sea or is it an extremely small plot squeezed in somewhere?

No, not a small plot, 800 m2
Located by the little river.
I think they don't want too much construction there.
If it all works out and it's a long way to go,
then I can sit on the porch and fish.
I have 140 m2 in my current house here.
40 m2 really too little and 140 m2 far too much.
There are plenty of plots that allow more than 40m2,
but we are not so interested in living on a piece of farmland
squeezed among a lot of others.
Better then to stay in the current house which has 4000 m2 plot.