The Fascinating Early Use Of Box Sash Windows

28/10/2016 - 3 minutes read

The fascinating early use of box sash windows

There are several notable examples of early sash windows, the most well-know of which are Chatsworth (c1676-1680), Ham House, Hampton Court Palace and Kensington Palace. These properties date back to the late 17th century and provide an interesting glimpse into their revolution – and evolution. It also spawned an emphasis on sash window renovation which led to the sash window revival of today.

Royal patronage

The fact that these buildings were built for Royalty gave them enormous prestige. Sash windows became a fashion statement in both old and new buildings, hence why builders continued to install them into ordinary dwelling places for many years after the 17th century. Indeed, they were seen by the expanding middle classes as de rigeur: they could emulate royalty.

There was also the aesthetic appeal and the practical superiority over more modern casement windows. The older wrought-iron hinged metal casement had meant, with their dark, weaker and draughty lead, using larger sheets of glass which was more restricted.

Old casement

One of the practical issues with the casement windows was that when they opened, they detracted from the outer façade, as opposed to enhancing it.

Contrast this to the new sash windows, with their gleaming white frameworks and larger sheets of glass, which added to the outer and inner appeal of the building.

The crown glass used in these early sash windows created eye-catching reflections that could not be replicated by the smaller panes of the earlier windows.

New sash

The new sash windows had thick glazing bars too, often made of oak, with the weight box positioned almost flush with the outer wall.

Therefore those who had the money to afford the new, and better, sash windows, ripped out the existing leaded light windows. This also explains why many of the more grand 16th and 17th century houses have early 18th century windows.

Sometimes this modernisation programme was undertaken on the main aspects of the buildings only and the less prominent parts were left with the casements intact.


This fashionable modernisation was therefore lavished only on the principal facades which could be seen by public and visitors, and early casement windows often survived on the less prominent facades.

Envirosash provides high quality sash window restoration services to London and the South of England. We restore, draught proof and install slim double glazing into existing period windows and doors. We also manufacture bespoke made to measure windows and doors, and all our joinery is crafted from Accoya wood.

Contact Alex on 0800 292 2309 today to arrange a free survey and quote with no obligation.