Glass & Glazing

The most common form of glass throughout the Georgian period was Crown glass. This was made by blowing, with a central bull's-eye, and had a unique sparkle. Plate-glass manufacture was too expensive to affect the design of sash windows until 1838, when sheet glass, a cheaper form, was introduced. At first, the use of the plate-glass was confined to the upper end of the market and, by the 1840's, owners of older houses were beginning to remove glazing bars from windows to the principal facades. By the 1850's, more expensive villas and terraced houses were built with plate-glass windows to front facades. Glazing bars were still used in basements, attics and on less important elevations.

The use of larger sheets of glass led to the introduction of horns on sash windows, which were basically a continuation of the style beyond the outer meeting-rail joint, providing a mortice-and-tenon joint, to give added strength to the meeting rails. Sash windows horns were moulded, one of the more usual designs being a variation of the ogee moulding. But this depended on the builder and the locality, and there were many regional variations. Later in the 19th Century, builders often adopted their own in-house style, as may be seen in many late 19th Century developments.

The most widely used design were four-paned sash windows. Sheet glass was common in Victorian Gothic villas and terraces, and by the 1870's the four paned sash was the standard for cheaper terraced houses, although there were regional variations. As a general rule, plate-glass was used only for the more important rooms. The use of glazing-bars, and the social hierarchy of glazing, depended on the builder and the area. In rural parts and poorer properties, glazing bars were employed throughout the period, as were casement windows.

In the 1870's and 1880's the influence of architects such as Philip Webb and Norman Shaw, and the Queen Anne Revival style, led to the return of glazing bars, which often imitated Queen Anne windows with Victorian modifications, such as sash windows horns. A popular design, particularly in the 1880's and 1890's, had glazing bars in the upper sash,with the lower sash a single pane or divided vertically into two. There were many variations on this theme.

Many patents were taken out for sash windows in the later 19th Century, One of these may be seen in hotels and public buildings in particular. This was a device which allowed the sash to pivot inwards to facilitate cleaning. The varieties were too numerous to mention here, but by the end of the 19th Century some extremely elaborate sash windows were made - often designed to sit behind Tudor-style mullions, and appear like casements.