When it comes to preserving and restoring sash windows, extra special care needs to be taken with the glazing, especially if it is still the original glass. The material is delicate and should be handled very carefully to avoid damaging it. If your window needs a repair and you want to retain its character and aesthetics as effectively as possible, professional assistance is needed.
Windows from the 19th century and earlier are likely to be made from crown glass. The early material was made using a very specific process where a hollow globe was created before being flattened and then cut to size. The glass is easily identifiable because it is slightly rounded and can contain air bubbles, which create unique lighting effects that cannot be replicated with modern glass. Both of these features add a great deal of character and distinguish properties dating from the period.
Crown glass is very highly sought after because the technique is no longer used to make windows. The existing stock is all there is, and that is very limited, particularly when you consider that the glazing may have been damaged and replaced over time. Those windows that still contain the material need to be preserved whenever possible so that the beautiful craftsmanship is not lost completely.
To avoid damaging the glazing, the panes should be removed from the window very carefully before restoration takes place. If putty has been used to hold or seal the window, it will need to be softened before it can be removed. Chipping it away when it is dry and solid can crack the pane, especially if it has been in place for a long period of time.
At David Humble we have a huge amount of experience with sash window restoration and provide services for property owners across Northumberland. We understand how valuable the original glass is and use a combination of modern and traditional techniques to minimise the risk of damaging it. You can rely on us to protect the window and see it restored to its best.