Hard panels formed from a wood-based material and having a decorative layer for floor coverings are provided, at least on two opposite edges, with coupling devices made in one piece with the panels wherein similar panels may be coupled together to form a floor covering, wherein these coupling devices provide for an interlocking in a direction perpendicular to the plane of coupled panels, as well as in a direction perpendicular to the edges concerned and parallel to the plane of coupled panels. These coupling devices are constituted of a tongue and a groove. The top side of the tongue has a protrusion that cooperates with a meshing recess located in the lower side of the upper lip of the groove of the coupling devices, and a portion extending generally parallel with the plane of the panel to form a contact surface cooperating with the lower side of the upper lip of the groove.