A flooring system, comprising a plurality of rectangular building panels (1,1') with long and short edges, and with hard surfaces, such as stone and tile, which are mechanically connectable to each other along one pair of adjacent joint edges (5a, 5b), each floor panel being provided with a flexible tongue connected to a first groove at a first joint edge (5a, 5b) and second groove at a second opposite joint edge (5a, 5b), said grooves are formed in one piece with the panels, for mechanically locking together said adjacent joint edges at right angles to the principal plane of the panels, thereby forming a vertical mechanical connection between the panels, said panels being provided with a first locking element at one of said first and second joint edges (5a, 5b) formed in one piece with the panel and a locking groove at an opposite first or second joint edge, the locking groove being open towards a rear side or a front side of the panel, wherein the flexible tongue is formed of a separate material, is flexible and resilient such that two panels, can be mechanically joined by displacement of said two panels vertically towards each other, while at least a part of the flexible tongue at said second opposite joint edge is resiliently displaced horizontally, until said adjacent edges of the two panels are brought into engagement with each other horizontally and the flexible tongue at said second opposite joint edge is then displaced towards its initial position, characterised in that each panel being provided with a second locking element at the other of said first and second joint edges (5a, 5b), formed of a separate material and connected to the locking groove, the first and second locking element form a mechanical connection locking the panels to each other horizontally parallel to the principal plane and at right angles to the joint edges, the second locking element is flexible and resilient such that two panels, can be mechanically joined by displacement of said two panels horizontally towards each other, while at least a part of the second locking element at said second edge is resiliently displaced vertically, until said adjacent edges of the two panels are brought into engagement with each other horizontally and the second locking element at said second edge is displaced towards its initial position against the first locking element at the first edge. each floor panel being provided with a flexible tongue connected to a first groove at a first joint edge (5a, 5b) and second groove at a second opposite joint edge (5a, 5b), said grooves are formed in one piece with the panels, for mechanically locking together said adjacent joint edges at right angles to the principal plane of the panels, thereby forming a vertical mechanical connection between the panels, said panels being provided with a first locking element at one of said first and second joint edges (5a, 5b) formed in one piece with the panel and a locking groove at an opposite first or second joint edge, the locking groove being open towards a rear side or a front side of the panel, wherein the flexible tongue is formed of a separate material, is flexible and resilient such that two panels, can be mechanically joined by displacement of said two panels vertically towards each other, while at least a part of the flexible tongue at said second opposite joint edge is resiliently displaced horizontally, until said adjacent edges of the two panels are brought into engagement with each other horizontally and the flexible tongue at said second opposite joint edge is then displaced towards its initial position, characterised in that each panel being provided with a second locking element at the other of said first and second joint edges (5a, 5b), formed of a separate material and connected to the locking groove, the first and second locking element form a mechanical connection locking the panels to each other horizontally parallel to the principal plane and at right angles to the joint edges, the second locking element is flexible and resilient such that two panels, can be mechanically joined by displacement of said two panels horizontally towards each other, while at least a part of the second locking element at said second edge is resiliently displaced vertically, until said adjacent edges of the two panels are brought into engagement with each other horizontally and the second locking element at said second edge is displaced towards its initial position against the first locking element at the first edge.