Sliding sash windows are made up of two glazed frames (or sashes), which slide vertically or horizontally to open. They date back to the 1600s and were particularly popular in the Georgian and Victorian eras.
Sash horns are downward protrusions from the base of the upper sash, fixed to either end of the horizontal centre bar of the frame.
These small additions to the window frame can be found in many decorative styles.
In the Victorian period the trend moved away from having lots of separate panes (or lights) in each sash. As a result, the glazing bars (also known as Georgian bars) were removed and replaced with one piece of glass.
Removing the bars made the frame weaker and so sash horns were added to strengthen the joints.
An extra benefit of the window horns was that they stopped the sash being opened too far and jamming.
Timber sash windows are still constructed with sash horns to strengthen the frame. But, for modern PVCu sash windows, sash horns are, structurally, redundant. However, many homeowners still choose to incorporate them for a more authentic appearance.
A Window Wise timber sliding sash window.
Window Wise PVCu sliding sash windows.