A frame assembly (1) for mounting doors and the like comprising a pair of jambs (2, 3) and a header (4) for connecting said jambs, and, where required, a sill, each said jambs and header and sill (5) where required being a compression molding of filler, waste, or recycled particulate material bound together by a thermoplastic binder, each said jambs (2, 3) and header (4) presenting when assembled an inwardly facing planar surface of a width to receive a door to be mounted in said frame assembly and an inwardly projecting door stop shoulder formation projecting inwardly of said planar surface.