Abstract: The joint thereshown has two stainless steel side plates (21, 22) which are rolled from a single strip and are bent double at the bottom of the lower limb (23) of the Y. The plates have rolled in ridges (24) at the top of this limb (23) and diverge above the ridges (24) as upper Y limbs (26). Between the limbs (26) a core is captivated at a relatively hard, necked lower core-portion or rib (31) by the ridges (24). Above these, a relatively softer upper core-portion or strip (32) fills the space between the upper limbs (26), tapering out with them. The core is a co-extrusion of the two portions (31, 32) joined by a neck (33). It is held in place by the ridges (24) being rolled around lower portion (31). This joint is fitted between tiles at a gap of the width of the ridges (24), by driving it between the tiles to compress the divergent upper Y limbs (26).