A flooring system, comprising a plurality of floor panels (1, 1') which are mechanically connectable to each other along at least one pair of adjacent first and second opposite joint edges, said panels (1, 1') being provided with a locking strip provided at said first joint edge, said locking strip extending beyond the first joint edge and being provided with a locking element extending in direction of a principal plane of the panels (1, 1'), a locking groove at said second opposite joint edge for receiving said locking element and thus mechanically locking together said adjacent joint edges (2, 3) parallel to a principal plane, the locking groove being open towards a rear side of the panel, wherein a) said locking element comprises an external edge with a recess with an upper locking surface, and said locking groove comprises an internal edge with a protrusion with an upper locking surface, or b) said locking element comprises an external edge with a protrusion with an upper locking surface, and said locking groove comprises an internal edge with a recess with an upper locking surface, wherein said protrusion engages said recess when two panels (1, 1') are mechanically connected to each other, so that in projection on the principal plane the upper locking surface of the recess and the upper locking surface of the protrusion overlap at least in parts, wherein at any given position of the overlap in any sectional plane of each panel (1, 1') which is perpendicular to the adjacent first and second opposite joint edges the upper locking surface of the recess is distanced further from the rear side than the upper locking surface of the protrusion to form a gap, said flooring system is characterized in that the upper locking surface of the recess and the upper locking surface of the protrusion at any given position of the overlap have a minimum distance (gap width) of 0.05 to 2.0 mm. a locking strip provided at said first joint edge, said locking strip extending beyond the first joint edge and being provided with a locking element extending in direction of a principal plane of the panels (1, 1'), a locking groove at said second opposite joint edge for receiving said locking element and thus mechanically locking together said adjacent joint edges (2, 3) parallel to a principal plane, the locking groove being open towards a rear side of the panel, wherein a) said locking element comprises an external edge with a recess with an upper locking surface, and said locking groove comprises an internal edge with a protrusion with an upper locking surface, or b) said locking element comprises an external edge with a protrusion with an upper locking surface, and said locking groove comprises an internal edge with a recess with an upper locking surface, a) said locking element comprises an external edge with a recess with an upper locking surface, and said locking groove comprises an internal edge with a protrusion with an upper locking surface, or b) said locking element comprises an external edge with a protrusion with an upper locking surface, and said locking groove comprises an internal edge with a recess with an upper locking surface, wherein said protrusion engages said recess when two panels (1, 1') are mechanically connected to each other, so that in projection on the principal plane the upper locking surface of the recess and the upper locking surface of the protrusion overlap at least in parts, wherein at any given position of the overlap in any sectional plane of each panel (1, 1') which is perpendicular to the adjacent first and second opposite joint edges the upper locking surface of the recess is distanced further from the rear side than the upper locking surface of the protrusion to form a gap, said flooring system is characterized in that the upper locking surface of the recess and the upper locking surface of the protrusion at any given position of the overlap have a minimum distance (gap width) of 0.05 to 2.0 mm.