Abstract: A method of building a triangulated frame structure of the kind composed of a plurality of subsidiary members (12) joined by their ends to a plurality of main members (7,8,11) intermedially of the ends of the main members (7,8,11). The method comprises forming the ends of the subsidiary members (12) as protrusile tongues (13); providing the main members (7,8,11) with locator slots (14) each able to accept one of the tongues (13), and located in the main members (7,8,11) at points to which the end of a subsidiary member (12) is to be joined; arraying the main members (7,8,11) and the subsidiary members (12) together substantially in correspondence with the position they are to occupy in the finished frame structure, entering the tongues (13) into that one of the slots nearest to it when the members (7,8,11,12) are in the arrayed position; and bending the entered tongues (13) so that they are at least partially restrained against withdrawal from the slots 14.