PRODUCTION OF STAIRS OF PRECAST CONCRETE

PROBLEM TO BE SOLVED: To reduce an expense for a form by a method in which a prescribed number of tread step parts having a triangular cross section are concrete- molded, after that, by concrete-molding stair floor parts, a prescribed number of the tread step parts are bonded integrally in the shape of saw teeth. SOLUTION: A form 10 for molding a tread step part comprises recessed parts 11 arranged in parallel, one surface of each recessed part 11 is a molding surface 12 for a tread surface, and the other surface is a molding surface 13 for a riser surface for concrete-molding the riser surface. By placing concrete in each recessed part 11, tread step parts 5 having a triangular cross section are molded simultaneously in a state in which they are separated from each other. By controlling the quantify of concrete to be cast in each recessed part 11, the tread steps 5 are finished in a desired prescribed rise size and a tread surface size. Both upper end molding surfaces 12, 13 of the recessed part 11 are used to the upper limit, concrete is placed to both upper end surfaces PO of each recessed part 11, the upper end of the concrete is leveled to be a plane which nearly coincides with the upper end surface of the recessed part 11.