A decking board system (1400, 1600), comprising at least one decking board, said decking board comprising: a first longitudinal side having a first member extending generally longitudinally outward therefrom, the first member having a first top portion (1418, 1418a), a first lower portion formed on an opposing side of the first top portion (1418, 1418a), an end portion positioned between the first top portion (1418a, 1618a) and the first lower portion, a first shoulder separating the first top portion (1418a, 1618a) from a top surface of the decking board, and a second shoulder positioned between the first lower portion and a bottom surface of the decking board; a second longitudinal side including a second top portion (1482b, 1582b), a second lower portion and an interior portion (1452b, 1552b) defining a cavity (1450b, 1550b, 1650b) therebetween to receive a first member of an associated decking board therein; said decking board system (1400, 1600) further comprising a sealing assembly (1420, 1520, 1620) configured to provide a seal between said decking board and an associated decking board; characterised in that said second top portion (1482b, 1582b) includes a lip member extending downward from said second top portion (1482b, 1582b); and the sealing assembly (1420, 1520, 1620) is configured to engage the first top portion, end portion and the first lower portion of the first member of the first longitudinal side, and wherein the sealing assembly (1420, 1520, 1620) has an edge (1464, 1564, 1664); wherein the lip member is configured to cooperatively engage the edge (1464, 1564, 1664) of the sealing member (1420, 1520, 1620), and wherein the engagement of the lip member and the edge (1464, 1564, 1664) forms a seal therebetween. a first longitudinal side having a first member extending generally longitudinally outward therefrom, the first member having a first top portion (1418, 1418a), a first lower portion formed on an opposing side of the first top portion (1418, 1418a), an end portion positioned between the first top portion (1418a, 1618a) and the first lower portion, a first shoulder separating the first top portion (1418a, 1618a) from a top surface of the decking board, and a second shoulder positioned between the first lower portion and a bottom surface of the decking board; a second longitudinal side including a second top portion (1482b, 1582b), a second lower portion and an interior portion (1452b, 1552b) defining a cavity (1450b, 1550b, 1650b) therebetween to receive a first member of an associated decking board therein; said decking board system (1400, 1600) further comprising a sealing assembly (1420, 1520, 1620) configured to provide a seal between said decking board and an associated decking board; characterised in that said second top portion (1482b, 1582b) includes a lip member extending downward from said second top portion (1482b, 1582b); and the sealing assembly (1420, 1520, 1620) is configured to engage the first top portion, end portion and the first lower portion of the first member of the first longitudinal side, and wherein the sealing assembly (1420, 1520, 1620) has an edge (1464, 1564, 1664); wherein the lip member is configured to cooperatively engage the edge (1464, 1564, 1664) of the sealing member (1420, 1520, 1620), and wherein the engagement of the lip member and the edge (1464, 1564, 1664) forms a seal therebetween.