a vee joint having a first flange hingedly connected to a second flange at an angle . a trough is formed between the first flange and the second flange and is used to retain joint filler within a joint interval in a concrete floor slab . the flanges are movable to facilitate the placement and retention of the vee joint within various sized joints in concrete slab flooring . when the vee joint is placed within a joint interval , the flanges may be spaced varying distances apart to accommodate joint filler therebetween and to intimately engage with the confronting walls of the floor slab to avoid bypass of joint fill material .