Victorian & Edwardian
A practice often seen in late Victorian and Edwardian villas was to run an elaborate moulded cornice or transom across the meeting rail. This was usually mounted on the box frame, with the sash operating behind it. Sometimes, however, the meeting rail itself had a miniature dental cornice, or was curved, as may be seen in districts such as Muswell Hill, North London. In the same districts can be seen elaborate multi-curved sashes.
By the turn of the Century, the sash was the most widely-used window. However, the use of steel windows and casements had grown with Revivalist styles, especially the Queen Anne, as may be seen in buildings designed by Norman Shaw and other architects, and the lead casement was beginning to make a come-back.
The growth in use of the casement increased during the Edwardian period, and by 1910 many houses were built with timber casements, with sash windows relegated to less important elevations.
After the First World War, although sash windows were still used in larger houses in the neo-Georgian style, the revival of vernacular styles, that took place before 1914 through architects such as Lutyens and Voysey, and the great popularity of the mock-Tudor style, led to the general adoption of wood and steel casements. (The latter were made in standard sizes by many firms, the two best-known being Henry Hope of Birmingham and Crittall of Braintree).
The construction of sash windows involved more sophisticated techniques and mouldings, with added labour costs, and this was probably one of the major reasons why mass-produced steel and timber windows were adopted generally after the First World War, particularly for housing estates. Some councils' building estates in the neo-Georgian style continued to use sash windows.