This invention describes ecologically sound, economical steel buildings with high insulation against noise, heat transfer and with fire protection, of low cost and speedy construction, and with potential for full, or in large part, energy self-sufficiency. These buildings consist of prefabricated components, which form internal and external walls, floors, ceilings and roofs, and which are constructed in the form, structure and strength specified in the architectural, structural and electromechanical design of the building to be constructed. The invention also describes a method of constructing buildings using prefabricated components, which can be placed by crane into slots which are either integrated, during manufacture in some of the prefabricated metal panels, or formed by the columns and beams in the corners of the building and its interior spaces.