Lexan roof with aluminum siding

OK, having flight of ideas (please try to keep up)
Thinking now of using aluminum outer skin on sandwiched walls. (Generic Benroy 59.5" outside wall-to-outside wall)
For the roof, would place Lexan (60"x96") (after laying a heavy bead of silicon adhesive/sealant) on top of wall edges, and trim flush with walls.
Then would use the aluminum trim piece to screw through the Lexan into the sidewalls (using sealant on each screw). This would also capture the aluminum siding, allowing floating.
Does this make sense?? Any problems you can think of??
Thanks
william

Thinking now of using aluminum outer skin on sandwiched walls. (Generic Benroy 59.5" outside wall-to-outside wall)
For the roof, would place Lexan (60"x96") (after laying a heavy bead of silicon adhesive/sealant) on top of wall edges, and trim flush with walls.
Then would use the aluminum trim piece to screw through the Lexan into the sidewalls (using sealant on each screw). This would also capture the aluminum siding, allowing floating.
Does this make sense?? Any problems you can think of??
Thanks
william