Pour stop

A steel angle or bent plate, used around the perimeter of a floor or opening to contain the concrete during placement. 

The SDI pour stop selection tables are published only up to a 12-inch slab overhang. For overhangs greater than 12 inches, SDI does not provide a standard gauge selection; the edge must be engineered (e.g., heavier gage, added stiffeners, or reduced overhang) based on project loads and support conditions.

Pour stop at slab edge