Abstract: A formwork includes a plurality of interconnectable disposable formwork elements for the casting of, for instance, foundations, sustaining walls, etc. in concrete and which is cheaper and wherein the formwork operation is rapidly effected, and at the same time it may be done by a person not skilled in the trade. Each formwork element (1) consists of an elongated, thin-walled, cylinder-shaped element, which is provided with coupling members on the neighbor element(s) for the interconnection of adjacent cylinder-shaped formwork elements so that, upon filling of concrete into the interconnected cylinder-shaped formwork elements, a row of fused concrete columns is formed constituting a wall on which the formwork elements may form the external surface(s) or from which the external portions of the formwork elements may be removed.