Abstract: The invention provides a rainwater guttering system comprising plastic trough shaped gutter lengths (1) in which one side wall (2) of each length is extended upwardly and reversed back on itself to form an inverted U-shaped clip (3) which fits over the upper edge (4) of a fascia board (5) which provides a continuous support. Adjacent gutter lengths are directly fixed together and supported at selected spaced points, the arrangement being such that any changes in length dimensions of the system due to temperature changes are accommodated by local buckling of the gutter lengths. Preferably, the system includes a fascia board (5) especially formed to present a continuous free upper edge.