There is disclosed a long trough (1) for mounting under a partitioning (2) between two stys (3, 4). The long trough includes a plurality of aligned, elongated trough elements. Each trough element includes at least one transverse wall (10) extending transversely of the trough element. Trough elements are made of polymeric concrete. In order to achieve a construction which is simple to mount and to produce, the transverse wall (10) is cast together with the sides of the trough element. At the top side of the transverse wall (10) there is provided a slot (19) adapted to receive the partitioning (2) and to support the latter.
