Part-time novice, KM.

Between the two buildings is required to fill the free volume.
Need a set of drawings on a spatial frame.
One side will be based on columns (step 3 m; see Appendix). Other points bearing on the existing wall and the roof.
No loads - only the snow and wind (near Peter). The top and sides are sheathed with steel sheets.
Permitted and other materials (eg. on the roof of the sandwich) is at the discretion of the developer.
Need a solution with the minimum weight.
Will be made and paid for 2-3 decision.