A furniture item constructed from single elements, capable of being coupled to one another and to other elements by means of hinges, such as for example the legs of a chair, table or the like and the lateral members of the furniture item, the final stiffening of the assembled structure being provided by an internal spider or brace comprising opposed arches, the arches terminating in wedge-shaped ends and thrusting towards the hinges under the action of a central tension member, which tends to bring the opposed arches of each pair of the spider towards each other, it thereby being possible to construct the furniture item without the use of glue, adhesive or the like and the storage and transportation volume being reduced until assembly, which may be carried out even at the installation by the user himself.