Modular support element adapted to form a support for a tread of a staircase

A support for treads (2) of a staircase comprising a plurality of interconnected, modular support elements, each of said elements comprising at least an upper wall member (3) and a lower wall member (4) which are substantially planar and adapted to take up horizontal positions when the staircase is assembled, the lower wall member (4) and upper wall member (3) of each element being adapted to rest on the upper wall member (3) and the lower wall member (4) respectively of contiguous elements;

• first adjustment and fixing means (5) for enabling the upper wall member (3) to be moved relative to the lower wall member (4) of each element in a direction substantially perpendicular to the wall members themselves and for fixing these wall members together in a predetermined position corresponding to a desired distance between them and hence of a desired value of the height of a riser of a respective step formed by the support element;
• at least one pair of holes (22) formed in the upper wall member (3) of each element and at least one pair of female threads (23) each of which is coaxial with one of the holes, the female threads being fixed to the upper wall member (3);
• at least one through-hole (29) and one through-slot (30) formed in the lower wall member (4) of each element, first and second screw members (31, 32) having respective threaded shanks, the through-hole (29) being adapted to be traversed by the threaded shank of the first screw member (31) and the through-slot (30) being adapted to be traversed by the threaded shank of the second screw member (32), each of the screw members also passing through one of the holes (22) of the pair of holes formed in the upper wall member (3) of the contiguous said element and being adapted to be screwed into the corresponding female thread (23) of said contiguous element so as to fix each said support element to the contiguous support element.