Help. Interpret drawing, what is in the space?

[zet]

Hi, I would like to know what is in the space between the first and second floor. I see that there is first drywall, then sparse paneling, and then plastic sheeting, and then what? What are the sparse paneling mounted on?

 

[Argastesnickaren]

The Glesen is nailed into the 48*220 beam which is drawn to the right of the circled area.
The beam is probably oriented the other way in reality but is drawn so that it is visible on the drawing.
In the void, there doesn't appear to be more like step-damping insulation but is, just as you write, an empty space.