the use of aluminium in architecture by the 1920s when it produced ornamental spandrel panels for the Cathedral of Learning and the Chrysler and Empire State Buildings in New York. The exterior of the A.O. Smith Corporation Building in Milwaukee was clad entirely in aluminium by 1930, and siding panels of Duralumin sheet from Alcoa sheathed an experimental exhibit house for the Architectural League of New York in 1931. Most architectural applications of aluminium in the 1930s were on a monumental scale, and it was another six years before it was put to use on residential construction. In the first few years after World War II, manufacturers began developing and widely distributing aluminium siding. Among them Indiana businessman Frank Hoess was credited with the invention of the configuration seen on modern aluminium siding. His experiments began in 1937 with steel siding in imitation of wooden clapboards. Other types of sheet metal and steel siding on the market at the time presented problems with warping, creating openings through which water could enter, introducing rust. Hoess remedied this problem through the use of a locking joint, which was formed by small flap at the top of each panel that joined with a U-shaped flange on the lower edge of the previous panel thus forming a watertight horizontal seam. After he had received a patent for his siding in 1939, Hoess produced a small housing development of about forty-four houses covered in his clapboard-style steel siding for blue-collar workers in Chicago. His operations were curtailed when war plants commandeered the industry. In 1946 Hoess allied with Metal Building Products of Detroit, a corporation that promoted and sold Hoess siding of Alcoa aluminium. Their product was used on large housing projects in the northeast and was purportedly the siding of choice for a 1947 Pennsylvania development, the first subdivision to solely use aluminium siding. Products such as by unpainted aluminium panels, starter strips, corner pieces and specialized application clips were assembled in the Indiana shop of the Hoess brothers. Siding could be applied over conventional wooden clapboards, or it could be nailed to studs via special clips affixed to the top of each panel. Insulation was placed between studs. While the Hoess Brothers company continued to function for about twelve more years after the dissolution of the Metal Building Products Corporation in 1948, they were less successful than rising siding companies like Reynolds Metals.