A decking system comprising: a plurality of joists spanning in parallel, spaced apart from one another; a plurality of deck boards each spanning transversely across the plurality of joists; and a ledger board spanning in a longitudinal direction transversely across a mounting end of each of the plurality of joists such that the plurality of joists are supported on the ledger board at spaced apart positions in the longitudinal direction of the ledger board; the ledger board comprising: a first upright side and a second upright side opposite one another and extending in the longitudinal direction of the ledger board between respective ends of the ledger board; a back wall formed at the second upright side which is arranged for mounting against an upright supporting surface; characterized by a plurality of stiffener ribs extending in the longitudinal direction along the back wall at the second upright side, the stiffener ribs being of equal thickness such that the second upright side is flat; a plurality of fastener apertures adapted to receive fasteners therein for fastening the ledger board to the upright supporting surface; and a plurality of ledger board joist connectors formed at the first upright side of the ledger board including at least one ledge portion spaced forwardly and outwardly from the upright side of the ledger board upon which a corresponding overhang portion of the joist is arranged to be engaged; the mounting end of each joist comprising: an overhang portion extending in the longitudinal direction of the joist beyond a remainder of the joist, the overhang portion being supported on said at least one ledge portion of the ledger board; and a hook portion extending downwardly from the overhang portion to be hooked onto the ledger board such that the hook portion is received between the ledge portion and the upright side of the ledger board and preventing sliding movement of the joist in the longitudinal direction of the joist away from the ledger board. a plurality of joists spanning in parallel, spaced apart from one another; a plurality of deck boards each spanning transversely across the plurality of joists; and a ledger board spanning in a longitudinal direction transversely across a mounting end of each of the plurality of joists such that the plurality of joists are supported on the ledger board at spaced apart positions in the longitudinal direction of the ledger board; the ledger board comprising: a first upright side and a second upright side opposite one another and extending in the longitudinal direction of the ledger board between respective ends of the ledger board; a back wall formed at the second upright side which is arranged for mounting against an upright supporting surface; characterized by a plurality of stiffener ribs extending in the longitudinal direction along the back wall at the second upright side, the stiffener ribs being of equal thickness such that the second upright side is flat; a plurality of fastener apertures adapted to receive fasteners therein for fastening the ledger board to the upright supporting surface; and a plurality of ledger board joist connectors formed at the first upright side of the ledger board including at least one ledge portion spaced forwardly and outwardly from the upright side of the ledger board upon which a corresponding overhang portion of the joist is arranged to be engaged; a first upright side and a second upright side opposite one another and extending in the longitudinal direction of the ledger board between respective ends of the ledger board; a back wall formed at the second upright side which is arranged for mounting against an upright supporting surface; characterized by a plurality of stiffener ribs extending in the longitudinal direction along the back wall at the second upright side, the stiffener ribs being of equal thickness such that the second upright side is flat; a plurality of fastener apertures adapted to receive fasteners therein for fastening the ledger board to the upright supporting surface; and a plurality of ledger board joist connectors formed at the first upright side of the ledger board including at least one ledge portion spaced forwardly and outwardly from the upright side of the ledger board upon which a corresponding overhang portion of the joist is arranged to be engaged; the mounting end of each joist comprising: an overhang portion extending in the longitudinal direction of the joist beyond a remainder of the joist, the overhang portion being supported on said at least one ledge portion of the ledger board; and a hook portion extending downwardly from the overhang portion to be hooked onto the ledger board such that the hook portion is received between the ledge portion and the upright side of the ledger board and preventing sliding movement of the joist in the longitudinal direction of the joist away from the ledger board. an overhang portion extending in the longitudinal direction of the joist beyond a remainder of the joist, the overhang portion being supported on said at least one ledge portion of the ledger board; and a hook portion extending downwardly from the overhang portion to be hooked onto the ledger board such that the hook portion is received between the ledge portion and the upright side of the ledger board and preventing sliding movement of the joist in the longitudinal direction of the joist away from the ledger board.