A set of building panels, each building panel has a decorative surface and a mechanical locking device for horizontal and vertical locking of similar or essentially identical building panels in an assembled position. An upper edge portion of a side edge of a first building panel and an upper edge portion of a side edge of a second building panel are, in the assembled position, juxtaposed to form a joint seal. The mechanical locking device includes a locking surface at the upper edge portion of the side edge of the first building panel configured to cooperate with a locking surface at the upper edge portion of the side edge of the second building panel. The two locking surfaces are configured to lock the side edge of the first building panel and the side edge of the second building panel in a direction parallel to the extension of the decorative surface.

A floor panel includes a core provided with an upper and lower surface, and a first and second core flank at a first and second side of the core, respectively. The floor panel includes a first coupling part and a second coupling part provided at the first side and the second side of the core, respectively. Each of the coupling parts includes an inner side flank, an outer side flank, and an upper portion flank connecting the inner side flank to the outer side flank. A portion of the first core flank and an upper portion of the outer side flank of the second coupling part are inclined such that when the floor panel is coupled to an adjacently arranged further floor panel these upper portions lie against each other for the purpose of providing a locking in a vertical direction.

A panel, which, at two opposite edges, includes coupling parts that allow joining by a downward movement, the coupling parts including a male part that fits in a female part, wherein the male part comprises a laterally protruding lip with at a lower side a downward facing support surface.