How do you put a cupboard against the wall at A?
Reminds me of sprayed concrete igloo houses, Cheap but impossible to furnish .... Aaaaah those architects!
Tar tiles, um ... after me the flood ...
If we really care about this structure, I would add 10'000 € to passivate it and put something other than these tiles ...
But there are wooden houses with straight walls to assemble yourself.
Not expensive because made in the assembly line and delivered in kit ... We would have to compare the prices.
Despite everything I like the aesthetics of the house in A ... Make it shorter with an annex with a flat roof?