Abstract: A device for use in constructing a support surface for pavers and paving bricks comprising a planar tread surface; two elongated complementary mounting members being disposed at respectively opposite ends of the device and extending over substantially the entire width of the device, adapted to overlap and interlock. Thus when two devices are arranged end-to-end the complementary mounting members are fitted together and overlapping one another to define a mounting area. Each mounting member further includes a fastener receiving means, the fastener receiving means being located such that when a portion of the mounting member overlaps a corresponding portion of a complementary mounting member, the fastener receiving means of the portions are aligned to receive a single fastening element.