Mechanical locking system for panels and method of installing same

A set of building panels comprising a first panel and a second panel, a first edge of the first panel being mechanically connectable to a second edge of the second panel, said first edge being provided with a first tongue and a first groove, which are formed in one piece with the first panel, and said second edge is provided with a second tongue and a second groove, which are formed in one piece with the second panel, for mechanically locking together said first edge and second edge at right angles to a principal plane of the first and second panels, thereby forming a vertical mechanical connection between the first and second panels, the first edge being provided with a first locking element formed in one piece with the first panel and the second edge is provided with a locking groove, the locking groove being open towards a rear side or a front side of the second panel, wherein

• the second edge is provided with a second locking element, formed of a separate material and connected to the locking groove,
• the first and second locking elements form a mechanical connection locking the first panel and the second panel to each other horizontally parallel to the principal plane and at a right angle to the joined first and second edges, and
• the second locking element is flexible and resilient such that the first and second panels are mechanically joined by displacement of said first and second 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 first and second edges 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.