A quick word before we start
And that is the Old Norse word vindauga, from vindr (wind) and auga (eye). It’s almost as if it combines protection from the elements and the ‘see-through’ properties of glass.
c. 100 AD
It’s believed that the first glass windows are made in Roman Egypt. However, most civilisations make do with holes in the wall.
Early medieval period
The majority of windows continue to be unglazed, as glass is extremely rare and very expensive. Oiled fabrics are nailed directly to the frame or stretched over the timber lattice to provide some additional protection. Later, shutters are widely used to provide security, privacy and reduce draughts.
1600s
During the late 17th century, glass becomes more readily available. Glazed sash windows grow in popularity, with timber shutters extensively used to improve thermal performance and give a secondary skin of protection. These have the disadvantage of shutting out light and so are not practical for use during the day.
1800s
Some Victorian buildings overcome this daylight problem by using box sash windows with pairs of glazed sashes to improve thermal or acoustic performance during the day. Other examples are found in the 19th and 20th century with pairs of wrought iron casements and in northern and central Europe, pairs of timber hinged casements.
1960s
The birth of modern secondary glazing. The aluminium extrusion industry, heavily involved in aircraft production during the war, expands into other markets including building products. Being lightweight, strong, corrosion resistant and capable of forming complex shapes, aluminium is an ideal material for curtain wall and window systems.
One pioneer is Chris Childerstone, who founded Selectagaze. With a background in aviation, Chris is particularly interested in the acoustic properties of secondary glazing. He initially focuses on commercial buildings in noisy locations, with projects for BEA at Heathrow, Beecham’s Great Western Road offices, Sainsbury’s HQ and the Hyde Park Hotel.
1970s
Energy crises throughout the decade mean that secondary glazing’s thermal properties become larger selling points, as people look to conserve heat.
1980s-2000s
The rise of double glazing leads to secondary glazing manufacturers discovering a new market in catering for older, protected buildings where original features shouldn’t be removed.
Selectaglaze begins a long-standing relationship with organisations like Historic England and SAVE, growing to become specialists in providing glazing for Listed and Heritage buildings.
2010s
The debate between retrofitting and rebuilding begins. Modern sympathetically designed secondary glazing plays a strong role in allowing older buildings to meet 21st century performance needs, in particular in addressing the urgency to improve thermal efficiency and help to meet net zero targets.
Present day
Product sustainability is vital. Today’s ongoing innovation and focus on sustainability allows for more and more recycled content to be included in the production of aluminium and glass.
What next?
New shapes, more innovative designs, safer security glass, glazing with even better thermal performance. The secondary glazing industry never stops moving.