Can holes be drilled in the 50 ft. Galvanized Steel Roll Valley Flashing?

Yes, you can drill through galvanized steel flashing.

Yes, you can drill through galvanized steel flashing. Mark the hole with a center punch, the indentation left by the center punch will prevent the drill bit from wandering. Make sure the sheet metal is clamped or secured to an expendable backer board. Drill holes in sheet metal with a twist drill. Always use safety glasses and gloves.