Patent ID: 8028486

Claim:
A floor panel comprising: a body having a wood fiber-based core; and a locking system comprising a tongue, a tongue groove, a locking element and a locking groove, the locking system at least at two opposite parallel joint edge portions of the floor panel for mechanical joining of the floor panel in the horizontal direction with similar floor panels, and the locking element including a first side surface and a second side surface, the first side surface facing toward the floor panel, and a second side surface facing away from the floor panel, wherein said locking groove is located within the core, wherein the locking system is designed for joining of the floor panel with a previously installed floor panel by inward angling and/or snapping in, the locking system having a first set of active locking surfaces, one of the active locking surfaces on the locking groove and the other on the first side surface of the locking element, and a second set of active locking surfaces above the tongue, the first and second sets of active locking surfaces for engaging with corresponding first and second active locking surfaces of the similar floor panels after the floor panel has been joined therewith to lock the floor panels together horizontally, wherein a portion of the active locking surface of the first set locking groove or a portion of one of the active locking surfaces of the second set comprises a recess having therein an elastically compressible material other than that of the body of the floor panel, wherein the elastically compressible material is arranged in the recess so the elastically compressible material directly contacts a corresponding active locking surface of a set of active locking surfaces so that when there is horizontal swelling of an upper region of the joint edge portions the elastically compressible material compresses in the horizontal direction to counteract the effect of the horizontal swelling of the upper region of the joint edge portions.