Abstract: Disclosed is an apparatus for screeding or trowelling concrete or similar materials. The apparatus has a turret, mounted on a mobile frame. A telescopic boom is mounted in cantilevered fashion on the turret. A machine head, mounted on the distal end of the boom, is rotatable about a vertical axis. An attachment, such as a screed or a trowel, is attached to the machine head. The level and angle of the frame can be set to a selected elevation relative to a rotating laser beam by raising or lowering three hydraulic legs. The machine head can raise or lower the attachment to set the attachment at a selected elevation.