The station was constructed by Messrs. Fox, Henderson & Co. and designed by Edward Alfred Cowper of that firm, who had previously worked on the design of the Crystal Palace. When completed, New Street had the largest arched single-span iron and glass roof in the world, spanning a width of and being long. It held this title for 14 years until St Pancras station opened in 1868. It was originally intended to have three spans, supported by columns, however, it was soon realised that the supporting columns would severely restrict the workings of the railway. Cowper's single-span design, was therefore adopted, even though it was some 62 feet (19 metres) wider than the widest roof span at that time. George Gilbert Scott praised Cowper's roof at New Street, stating "An iron roof in its most normal condition is too spider-like a structure to be handsome, but with a very little attention this defect is obviated. The most wonderful specimen, probably, is that at the great Birmingham Station…" When first opened, New Street was described as the "Grand Central Station at Birmingham" by Richard Foster.