Glass

As with the majority of materials and techniques, there has been a vast improvement in glazing products for our industry. Traditionally, windows and doors were glazed with a single pane of glass, sealed with linseed oil putty. This method provided very poor heat efficiency, condensation issues and a lack in safety.

With demand always increasing for homes to become more economical, glass plays a vital part in a door or windows overall thermal value. The glass we use as standard in our products is a high performance 24mm – 28mm thick, double glazed unit which is low-emissivity (otherwise know as low-e glass).

Basically, low-e glass is a type of energy efficient glass designed to prevent heat escaping through your windows to the cold outdoors. The way is works is thanks to an invisible coating that acts as a poor radiator of heat and does not allow heat to be transferred to the outside. Instead, the low-e coating actually reflects the heat back into your room, keeping your home warmer and your bills lower!

In times that a modern double glazed unit is unacceptable for a project such as, heritage work or in some listed buildings, we are able to source a vast variety of alternatives to meet project requirements through our local supplier.

A question that we frequently get asked regarding glazing bars, is why we use applied bars (glazing bars that are stuck onto the internal and external faces of the glass). The answer is really very simple when you begin to understand the evolution of glazing.

Old Georgian glazing would comprise of lots of small, 4mm glass pains, divided up with beautifully thin (18-25mm) solid glazing bars, which would be mortise and tenoned into the frame or sash. Because these pains are so small and light, they would only require a small rebate to house and seal the pains, thus being the reason why such fine glazing lines could be achieved.

The Victorian era developed ‘plate glass’ which was much stronger and could be made in larger pains. This is why it is very typical to see Victorian windows with one vertical glazing bar running through the centre of the window, still maintaining these thin bars.

When double glazing was invented, it became very desirable for wooden windows and doors. A double glazed unit has a ‘warm edge spacer bar’ running round the edge of the unit which bonds and seals the pains together. Because of this and along side increased thickness and weight of the units, these thin and elegant glazing bars could not accommodate double glazing. Instead, early double glazing (which required glazing bars for aesthetic reasons) would adapt the same method, only with an increased bar thickness (often 45mm). This method looks unsightly and completely non traditional in appearance.

We can now get double glazing which can be broken up into, effectively, numerous pains with back to back spacer bars. These spacer bars are set between the two pains. With the addition of strong, modern glazing tapes we can now apply thin bars to the glass face, aligning them up with the spacer bars to give the appearance of individual pains. This method allows a modern window or door to maintain the aesthetic character of Georgian or Victorian glazing, but with increased thermal values and security. This method is also more cost effective.

If you have a project you would like us to quote for please feel free to contact us