JOIST

ceiling or floor support in building construction. Joistsof timber, steel, or reinforced concreteare laid in a parallel series across or abutting girders or a bearing wall, to which they are attached, usually by metal supports called joist hangers, or anchors. The ends of the joists are grooved or notched so that they are flush with the weight-bearing elements to provide a smooth horizontal. Before the floor is laid above or the ceiling laths hung below the principal joists, additional strength may be given in the form of bridging joistsdiagonal braces between the horizontal beams.