How to combine lofted surfaces into a solid

I am trying to loft 3 surfaces into a closed box so I can then input the information into honeybee for future analysis.
But I am quite confused about which component to use for combining them into a closed surface.
Can someone help please?loft to solid.gh (154.3 KB)

IMHO, you are using Loft too much in unnecessary places.

loft to solid_re.gh (149.4 KB)

Thank you very much!!!

Just note that you might run into trouble when running an analysis on curved geometry.
See, for example,