A "factory to make factories" is how Matthew and Mumby Ltd. describe the new precast concrete plant which they erected recently at Denton, near Manchester. To allow complete mechanization with unrestricted working space and a high daylight factor, three of the buildings were designed as a series of 90 foot span concrete arched frames linked by hipped double glazing. The buildings consist of a 250 foot long casting shop, a 150 foot barbending shop, and a 50 foot mechanics shop. The arched frames were entirely precast and were tied with external prestessing cables at the intersections of the arches and their columns. Each arched frame consists of 22 precast elements- 14 identical center elements, 6 feet long by 15 feet wide; the two end blocks of the earth; and three V section tapered column elements. The precast elements of a frame were cast at the site in timber forms as near to thief final positions as possible.