Hey guys, I'm trying to guess (for pre-design purposes) how thick of steel plate would be for a simple canopy over a window. Imagine a piece of plate steel bent into an L shape with the vertical leg 8" tall and bolted to the wall. The horizontal leg projects from the wall 18" and should not see any vertical loading other than gravity and rain. (Tempe, AZ) How thin can the plate be without sagging? 1/4"

Thank you for the insight!