A new British technique has made possible a sharp reduction in construction costs on the pictured concrete shell roof covering a 200,000 square foot area over a clear span of 180 feet. The long span and the reduction in cost are made possible by the use of latticed steel arches to support the concrete shells and their formwork during construction. The economy of this system of construction is in part a result of the fact that the roof permits economical superstructure and foundation designs, since only bending moments due to wind loads are transmitted to the supporting columns and end walls. Clear spans of between 80 and 210 feet are readily obtainable with point loadings up to 10 tons from any point in the roof. To reduce roof volume and save heating costs, the arches are designed with a rise of only one-tenth of the total span. The A. T. A. Industrial Company, Ltd. of Bristol, England, in association with Modern Engineering, Ltd., also of Bristol, are the license holders for the new so-called Siberkuhl method.