A brick-laying apparatus comprises a work platform vertically movable within a vessel and capable of rotating about the vertical axis of the vessel; and a robot for manipulating and laying bricks along the brick lining of the wall. The robot is mounted on a support capable of pivoting about a first vertical axis. To increase the effective radius of the robot, the support is mounted on an extension piece pivotable about a second vertical axis. The brick-laying apparatus is particularly well suited for repairing the refractory covering of a metallurgical converter.