Single Glazing

What is single glazing?

Single glazing is a window that has one glass pane, instead of double glazing which has two. This glass pane is typically held in with putty, then shaped to a 45 degree angle to allow water runoff.

Why should I buy single glazing?

People will always need single glazing. Typically, they want it through a desire to retain the original character of their sash windows or to satisfy listed building requirements. Whilst we specialise in traditionally designed double glazing, true purists won’t settle for anything less than the real thing. If you have a specific need we can source special hand-made glass replacements. We also salvage unusual pieces of period glass whenever we can. If you’re lucky, we might even have a few pieces that you can’t get anywhere else!


The loss of traditional windows from older buildings poses one of the major threats to British heritage. Traditional windows and their glazing make an important contribution to the significance of historic areas. They are an integral part of the design of older buildings and can be important in their own right, often made with great skill and ingenuity with materials of a higher quality than are generally available today. Modern glazing cannot easily copy the distinct appearance of historic hand-made glass. Because this appearance is so hard to copy, we offer a range of traditional glass options for listed buildings or conservation areas.

Windows are particularly at risk since they can be easily and often cheaply replaced. Such work often has a big effect not only on the building itself but on the way the street and local area looks. New windows have become a greater threat than ever to the character of historic buildings, since now there’s more emphasis on making current buildings more energy efficient.

Glass was hand blown into a hollow globe, also known as a ‘crown’. This ‘crown’ was then spun around at rapid speed, and began to flatten due to centripetal force – much like how spinning a lump of pizza dough will form a thin & flat circular base. These sheets of crown glass were already rather small, but the outer edges were thinner and weaker than the central mass. As a result, usable sections were cut from the central mass, thereby greatly restricting the maximum size of an individual pane.

Glass was hand blown into a hollow ‘sausage’ shape and the two ends were removed, resulting in a glass tube or cylinder. Whilst still molten, shears were used to split the cylinder down the middle and the glass was then flattened on an iron plate resulting in imperfect glass sheets. This process later became industrialised in the form of Cylinder Blown Sheet Glass.

Sheets of Broad Sheet Glass undergo an additional process of laborious hand grinding and intense polishing, resulting in a mirror-perfect finish.

Glass was hand blown into a large, cylindrical mould. This mould was then swung in a large trench to ensure that the molten glass spread evenly over the inner surface of the mould. Once the mould was opened, the cylinder of still-malleable glass was cut down the middle and flattened on to a table. This created much larger sheets than the Crown Glass method was capable of, without the imperfections typically associated with hand-formed Broad Sheet Glass.

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