Abstract: A fence or railing is disclosed which comprises a generally square vertical post formed, along each outer wall, with a U-shaped channel running its full length; the sidewalls of the channels defining two guide slots and the post further having a non-circular central open-ended bore. This central bore slidably and snugly receives, at its lower end, a pedestal which is fixed to a base plate. Mounted on the post is one end of an area-separation section made up of a top and a bottom horizontal rail interconnected by spaced vertical struts. The ends of the rails are inserted into one of the post channels and kept apart by flat spacer elements of identical constant cross-sections and lateral wings slid in the guide slots of the post channel. One spacer element keeps the bottom rail away from the base plate while a second spacer element separates the two rails from one another.