A sectional piece of furniture comprising at least one vertical columnar load-bearing member, and at least one functional member (13, 13.0, 13.01, 13.1, 13.2, 13.3, 13.4, 13.5, 15.2) of the piece of furniture, wherein: • said at least one columnar member comprises: - a plurality of structural blocks mutually vertically overlapping, each having a respective through hole (15.0) with vertical axis, aligned with the vertical axes of the through holes of the other blocks of said plurality of blocks, and a top member (15.2) having a respective through hole with vertical axis aligned with the vertical axes of the through holes of the other blocks and in which a threaded axial bushing is secured; - a vertical core shaped as a connecting tie, passing through said holes (15.0) of said plurality of structural blocks of said at least one columnar member, and having at least the upper end threaded and engaged by screwing into said threaded bushing of said top member (15.2); • said at least one functional member (13, 13.0, 13.01, 13.1, 13.2, 13.3, 13.4, 13.5, 15.2) comprises at least one support member partially protruding with respect to said at least one columnar member, characterized in that it comprises interconnecting means, in twos, of the blocks of said plurality of structural blocks; in that said at least one support member comprises at least one plate-shaped support means (12.1, 12.2, 12.3, 12.4, 12.5, 12.6) partially arranged and secured between two adjacent structural blocks of said at least one columnar member, partially extending with respect to said at least one columnar member itself, and supporting said at least one functional member (13, 13.1, 13.2, 13.3, 13.4, 13.5); and in that said at least one plate-shaped support means (12.1, 12.2, 12.3, 12.4, 12.5, 12.6) is secured between said two adjacent structural blocks by means of interconnecting means of said two adjacent blocks themselves. • said at least one columnar member comprises: - a plurality of structural blocks mutually vertically overlapping, each having a respective through hole (15.0) with vertical axis, aligned with the vertical axes of the through holes of the other blocks of said plurality of blocks, and a top member (15.2) having a respective through hole with vertical axis aligned with the vertical axes of the through holes of the other blocks and in which a threaded axial bushing is secured; - a vertical core shaped as a connecting tie, passing through said holes (15.0) of said plurality of structural blocks of said at least one columnar member, and having at least the upper end threaded and engaged by screwing into said threaded bushing of said top member (15.2); - a plurality of structural blocks mutually vertically overlapping, each having a respective through hole (15.0) with vertical axis, aligned with the vertical axes of the through holes of the other blocks of said plurality of blocks, and a top member (15.2) having a respective through hole with vertical axis aligned with the vertical axes of the through holes of the other blocks and in which a threaded axial bushing is secured; - a vertical core shaped as a connecting tie, passing through said holes (15.0) of said plurality of structural blocks of said at least one columnar member, and having at least the upper end threaded and engaged by screwing into said threaded bushing of said top member (15.2); • said at least one functional member (13, 13.0, 13.01, 13.1, 13.2, 13.3, 13.4, 13.5, 15.2) comprises at least one support member partially protruding with respect to said at least one columnar member,