A Brief History of Wood Windows & Our Sash Window Heritage
Like any industry, the history of windows has evolved over time and if you're visiting this section of our website, you're probably interested in what these changes have been that have shaped our built environment. That's why we've researched and written for you a brief history of the some of the key milestones in the development of glass and the sash window.
History of Glass
The complex nature of glass has intrigued man from ancient times. For one, its physical structure does not conform to liquid, solid or gas - it's actually more of a liquid than the solid it appears to be.
5000BC The first reference to glass comes from Roman historian Pliny in 77AD who suggested man first produced glass accidentally in 5000BC when sailors on a beach put their cooking pots on blocks of soda instead of rocks and as the fires heated up, the sand and soda combined turned into molten glass.
2500BC Ornamental glass beads dating from 2500 B.C. have been found in Egypt, and glass rods from even earlier have been uncovered in Babylon.
1500BC Egypt As with many innovations, it was the Egyptians who turned their to hand to practical application of materials rather than just decorative and using metal rods attached to silica paste cores dipped in molten glass, produced the first bottles.
250BC Babylon The discovery came that molten glass could be blown into shapes. and glass vessels suddenly became easy and inexpensive to produce.
200BC Roman Empire The Romans took this one stage further and with the help of Syrian and Babylonian glassmakers started to produce small bowls, bottles and cups.
Late 12th Century Following the collapse of the Roman Empire, developments in glass slowed right down and some say, it even almost disappeared with the exception of some Gothic cathedrals boasting highly expensive and extravagant coloured glasses.
13th and 14th Century: Italy Glassmaking started to enjoy a revival in Venice with the development of soda-lime. The news of this new thin glass 'cristallo' soon spread across the Alps to Germany, England, France and Belgium.
17th Century: England. In about 1675, the English learned to add lead oxide to the basic glass formula, and the resulting solid, heavy and durable vessels progressively replaced the fragile glasses of Venice.
Flat glass for windows was still rare during much of the 17th and 18th centuries. Small panes were made by blowing a large glob of glass, removing it from the blowing iron and then rotating the glass quickly so it would spread and flatten. Such glass had a dimple in its center, many air bubbles and a pattern of concentric circles, but it was transparent and effective in keeping out the weather. At the end of the 17th century, the French learned how to grind and polish cast glass to produce plate glass, but only the rich could afford it.
19th Century Suddenly glass technology exploded. A hand operated mold negated the need for blowing individual bottles and a semi-automatic bottle machine perfected in the middle of the century began the process of mass production.
Flat glass was coming of age with the introduction of compressed air technology and large relatively cost effective glass lites began to be produced. By the 1860s, glass-enclosed "wind eyes" became commonplace in the humblest homes. Plate glass also became popular, and with the addition of water power, grinding and polishing of heavy glass plates became faster and easier. By the 1860s, glass became commonplace in the architecture of Europe and North American commercial buildings.
20th Century: With the 20th century came an era of technology and automation for mass production to continuously churn out sheet glass (used for windows) that could easily be polished and ground simultaneously on both sides to produce float glass on beds of molten tin.
These developments continue with huge advances in processing for different colours, thermal efficiencies and strength, and all go into the next generation windows with which we're familiar today.
History of the Sliding Sash Window
The origins of the vertical sliding sash window are the source of much debate, with the earliest, in a very primitive form dating back to Europe in the 13th Century as little more than a vertical timber sliding shutter. Although the word 'sash' is actually derived from the French chassis meaning a frame, there's little argument that the sash window is traditionally British and closely associated with our Georgian, Victorian and Edwardian architecture. In fact, many conservation historians believe that the design is probably derived from the simple horizontal sliding sash, more commonly known as the Yorkshire Sash.
The earliest known use of sash windows in this country was in the later part of the 17th Century at Chatsworth, Ham House, Hampton Court Palace and Kensington Palace. Royal patronage and Sir Christopher Wren's endorsement made sash windows highly fashionable in both old and new buildings, and they represented something of a status symbol. People who could afford these new sash windows ruthlessly cut out their leaded light window which explains why so many larger 16th and 17th Century houses have early 18th Century windows.
The Georgian period embraced sash window design, improving it from a single moving sash, with the top being fixed, to the more familiar system of two moveable sashes. Oak was the common timber used for construction, with thick glazing bars to hold the small, valuable crown glass panes, made by blowing. As glass manufacture improved, larger panes started to appear and the 'classic' Georgian design consisting of six over six panes, with narrow glazing bars became the norm.
For the Victorians, box sash windows were a central focus to the character of their buildings with a focus on ornamentation and decoration inside and outside their homes. Curved horns, multi-arched heads, intricate mouldings, leaded lights and latticework started to appear in the sashes, which were often grouped into impressive bays and offset with ornate stone reveals. Graduating the size of windows from the ground upwards not only improved the perspective but also increased the amount of light to the lower rooms.
By the turn of the century the sash was most popular form of window, but after the first world war, this trend started to decline - many believe this was due to the higher labour costs compared with mass produced simple wooden casement. Fortunately though, in recent decades this decline has started to reverse with a growing appreciation of conservation, heritage and craftsmanship. ERW is proud to support this revival.