Abstract: The present invention refers to a method for controlling the vertical adjustment of a levelling and compacting plank drawn by a road-construction machine. During the working procedure the level of the plank, which is in floating contact with the material, is adjusted automatically. The present invention aims at preventing undesirable lifting of the plank caused by material which is located ahead of the plank and the flowability of which was changed due to an interruption in the motion of the machine. Hence, the invention employs the feature that, when the travelling mechanism is switched on, lifting of the plank, which is blocked against lowering when the machine is standing still, is blocked as well and that the blocking is eliminated only after a predetermined period of time.