Improvements in slab on ground formwork design and installation

A formwork support fin peg (14) comprises an elongated steel peg body (11) having a pointed lower end (11a), two triangular fins (12) made from steel plate welded to opposing sides of the body (11) about halfway along its length, and the body (11) having an upper section comprising a plurality of spaced holes (13) drilled though the peg at nominal 40 mm centres (spacings). The fins (12) act as depth markers as well as maintaining rotational orientation of the fin peg relative to the slab to be formed. An adjustable rebate bracket (27) is then installed over the top of the peg (14). The adjustable rebate bracket (27) comprises a support arm (28) having a socket (33) at one end, and a vertical plate (29) with predrilled holes 30 at another end which is welded to support arm 28 at 90 degrees. A rebate board (31) can be screw fixed (32) to the vertical plate (29).