These original Edwardian sash windows had been reglazed in the late 90s using thin double glazing.
Double glazing an existing window throws up a handful of challenges:
Firstly, the rebate depth of the sash needs to accommodate the extra thickness of the glass and still leave room for some form of facing to retain the glass. In this case, the fitter had resorted to a very thin bead of mastic.
Secondly, the extra weight of the glass in the sash needs to be counterbalanced by the weights in the sash box. The fitter had achieved this by adding a number of make-weights on top of the original weight. The length of all these weights meant that the window never properly closed again and would snag when opened, leading to the owner essentially abandoning use of the window.
To restore use and proper closure of the window, we opted to replace the weights in the box with a heavier material that would take up less space and allow for free movement. Although apparently straightforward, removing the weights was an awkward job involving painstaking use of seemingly every long, flat item in the tool kit.
5 “naughty little sausages” later, we discovered and removed the original weight. It was then a simple case of replacing the weights appropriately and hanging them from new long-life sash cords before re-fitting the window and perfecting the closure position.
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