This situation appears in a new high rise Office building.
The building has 4 basements, in these levels structural columns and retaining wall are located in the boundary line. But inside the building usable area would start at a certain distance from the structural wall (6 meters). During these four levels this instertitial area was considered as a void beacasue there was not slab between the structural wall and the usable area wall (inner wall).
But, now for structural reasons a slab shall be done connecting the inner wall and the exterior retaining wall. Does it mean that the floor area increases?? considering So that this area cannot be used anyway because the inner wall cannot be moved or opened, also due to structural reasons:
In wich category should I put this area??
Or, shall I consider the inner wall the boundary line?
(For example: Similar situation would happen in a level with a porch or balcony, except that in this case there is also wall between the columns)