Many older wooden windows have smaller panes of glass in a sash and the glass is separated by small pieces of wood called glazing bars. These types of windows are often referred to as multi-pane sashes and they can be found in fixed frames, double sashes, casements, awning and sliding windows.
The origin of glazing bars goes back to when only small panes of glass were affordable to be made. As glass technology advanced, larger panes became affordable, meaning less or no glazing bars were required. Glazing bars add character and often represent the architectural or design period of a building. For example with double hung sashes, in many heritage windows each sash contains six panes on the bottom and top sash i.e. 12 pieces of glass. In the 1930-40’s it’s more common to find two panes per sash and of course later windows have one pane per sash.
A challenge home owners face is striking the balance between conserving heritage or architectural features and at the same time improving the comfort and energy efficiency of the building and still keep the original windows and look.
This is where Glavenir vacuum insulated double glazing provides a solution that no other products on the market can do.
Traditional double glazing is often chosen to upgrade window performance. Typically it is 18-22 mm thick and presents many problems for retrofitting into existing wooden windows and doors. For more information about these issues click here.
If you have a builder advising you need to get rid of your old wooden windows……. beware and think twice! It’s likely they have come to this position because they cannot confidently fit traditional double glazing in your old frames and they don’t know about better alternatives such as Glavenir.
Throwing away your old timber frames is not the answer to keeping originality, value of the building and nor is it sensible as the timber is superior to new timber or alternatives such as plastic and aluminium.
Glavenir is only 6.1 mm so it fits in existing wooden sashes and we have a solutions to maintain the existing glazing bars or faithfully reproducing the original look.
If glazing bars are thick enough we can maintain their internal side and use one piece of glass for the whole sash! On the external side we place new bars over the glass to match the originals. Its a technology that’s been around in the northern hemisphere for a number of years and is perfectly acceptable.
If we cannot use the original internal glazing bars, because they may be too thin, we can place on the inner and outer surface of the glass new ones that replicate the originals.
It’s true that this solution may require a small compromise – sometimes the loss of the original glazing bars for new ones. But the upsides definitely outweigh the down. The use of one piece of Glavenir vacuum insulated double glazing with new surface mounted glazing bars provides the following advantages:
- Triple glaze performance will drastically improved comfort and energy efficiency.
- Less cost associated with installing one piece of glass per sash versus multiple panes per sash and working around glazing bars
- A stronger sash with less chance of water ingress through putty lines on original the outside multi glazing bars.
Below you can see a project we completed and the client is extremely happy with the result or you can view the project by clicking here.
Below are photos showing how a genuine 140-year-old double hung window can look after we install only one pane of glass in each sash and rebuild replica glazing bars to match for the inner and outer surfaces. The result is superb and now this window is one of the best performing windows in Australia, beating any new window. – You can learn about how to understand double glazing performance by clicking here.
