Yes,the structure is metalic.The slab is concrete on corrugated steel formwork but no concrete attic. I see two solutions:
A) The slab has a stopper for horizontal insulations, for the vertical attic is used only the curtain wall sistem with back facing panel. The problem is the where do you fasten the waterproof membrane?
B) The slab has above a metalic structure for the attic,backing the curtain wall.The wp membrane is fixed on the metalic profiles, but it's more complicated structure.
Tell me what do you think.

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