Abstract: Climbing formwork for use in the erection of reinforced concrete structures in which the raising of the formwork from storey to storey is carried out by the use of movable vertically extending members the height of which when fully extended is in excess of the height of two storeys of a building to be erected, the members being maintained in their correct vertical positions by supporting tubes set into the concrete of the structure. The members carry between them beams or the like for supporting the outer forms and preferably some or all of the inner forms used for pouring the structure and are raised to a height equivalent to that of one storey of the structure after the completion of the pouring of the concrete of a storey. The vertically extending members are preferably in the form of double acting hydraulic cylinders having a piston extendable under hydraulic pressure, the extension of the piston being utilized for raising the forms.