Trouble creating solids?

Hello,

I am trying to plug my data into opennest but I was told by a peer I cannot as my floorplates are not solid and the column holes are not cutting through. how can I fix this? I have attached my grasshopper file and it is an issue with both definitions.
280 proj 2.gh (67.4 KB)

You need to graft the first two inputs. Otherwise the Brep Join tree structure is incorrect.

B output now shows 80 Closed Breps.