The tool re-positions a floor guide supporting a climbing screen. The climbing screen includes a mounting arm that extends along a longitudinal axis and is fixed to a floor of a construction. The tool includes a first member fixable to the floor of the construction at a first position along the axial length of the mounting arm, a second member fixable to the mounting arm at a second position spaced along the longitudinal axis of the mounting arm from the first member, and a driver linking the first and second members to one another and operable for varying the spacing between the first and second members along the longitudinal axis.