Abstract: The present invention relates to a three dimensional metal framework, designed for forming isothermic walls of buildings, which comprise an inner air cavity in form of a blade along one of its faces.This framework (9) comprises rectilinear and parallel rods (14) which are welded, in at least two parallel rows (14a, 14b), on sinusoidal wires (15) which extend in planes perpendicular to the rectilinear rods and whose tops (15a, 15b) are situated in two planes parallel with the two rows of rectilinear rods, the first row (14a) of rectilinear rods being furthermore slightly spaced apart from a first one of the planes containing the tops (15a) of the sinusoidal wires.The invention also relates to a constructional element built from this framework and comprising a bearing wall (4) and a heat insulating layer (5) both disposed between the two rows (14a, 14b) of the rectilinear rods of the framework (9) as well as two finishing coverings (2b, 3b) formed on the tops (15a, 15b) of the sinusoidal wires of the latter.