Abstract: Proceeding for the construction of light self-supporting walls, which being able to be assembled in situ as from panels previously produced, destined to the closing of spaces between ceilings and floors of buildings; this proceeding characterized because it includes the following steps: a) producing rectangular, self-supporting panels with expanded polystyrene its density being at least 20 Kg/cm3; b) as from the floor of application, setting up the panels fixing its inferior borders against the floor and joining the different panels one with the other by their side borders by means of an adherent compatible with polystyrene; c) on the main faces of the set up panels apply an adherent material until its covers all the surface in an uniform way; and d) covering the main faces with a termination lining or layering.