A Los Angeles contracting firm has just completed a demonstration house using an entirely new system of casting reinforced concrete walls. The system is said to reduce overall construction time by as much as 70 percent. Heart of the method is the use of mass production techniques in site or factory precasting 6 inch thick reinforced concrete walls with vertical cores running full length. Ellis White, chairmen of the board and engineering vice president of Concrete Cored Construction Company, created the system of construction, which he calls Corecast. Some observers predict that Corecast may do for concrete what the rolling mills did for steel. The exterior walls of the Corecast house are a series of linked I-beams formed around 14 by 4 inch voids. During casting the void forms are accurately positioned by aluminum end forms. The aluminum casting forms permit walls to be made to within 1/32 inch accuracy. As soon as the concrete hardens sufficiently, the outside forms are stripped and the core forms pulled, leaving a wall with voids in it. A vital part of this engineered approach to concrete housing is the development of a new fast-setting portland cement. The cement is similar to the Portland Cement Association's experimental regulated-set cement. White reformulated PCA "reg-set" to his own needs to achieve impressive compressive strengths, such as 2050 psi in 24 hours, 900 psi in only one hour. The 28 day compressive strength is 5200 psi. Forms can be stripped the morning after casting.