Abstract: Apparatus for creating a step or break in level of a poured concrete building slab, said apparatus comprising a length of section of suitable height and closed or open cross-sectional shape supported upon a plurality of discrete chairs which are, in turn, fixed to supporting formwork by suitable fastenings; said chairs being unitary or comprising height-adjustable elements; said section providing level references to which the surfaces of the higher and lower parts of said concrete slab are finished and acting as a riser between the two said surfaces; said section and said chairs being left in place in said concrete slab following its curing.

Abstract: An elongated hollow mould for the integral formation of a raised sill or hob on the surface of a cast-in-situ concrete building slab, said mould comprising two generally parallel, continuous side panels joined in fixed spatial relationship at their upper and lower edges by spacer elements which permit the entry of concrete from above and the passage of concrete there through to formwork below upon which said slab is to be formed, thereby making the concrete within said filled mould contiguous with that of said concrete slab beneath; said mould being supported upon a plurality of discrete chairs, each said chair comprising two narrow, parallel, vertically oriented side panels joined at their lower ends by a transverse bottom part fixed to said formwork, said mould being supported in a said chair by a height-adjustable transverse bridge fixed to said chair side panels.

Abstract: An elongated hollow mould for the integral formation of a raised sill or hob on the surface of a cast-in-situ concrete building slab, said mould comprising two generally parallel, continuous side panels joined in fixed spatial relationship at their upper and lower edges by spacer elements which permit the entry of concrete from above and the passage of concrete there through to formwork below upon which said slab is to be formed, thereby making the concrete within said filled mould contiguous with that of said concrete slab beneath; said mould being supported upon a plurality of discrete chairs, each said chair comprising two narrow, parallel, vertically oriented side panels joined at their lower ends by a transverse bottom part fixed to said formwork, said mould being supported in a said chair by a height-adjustable transverse bridge fixed to said chair side panels.