A Sweet Sash Window Repair

Earlier this month, about two weeks ago, sometime around 09/07/2020, I secured some work from the estate agents. It was my first decent job from them since the lock-down. A schedule of work involving repairing a hole in the wall, sticking back some tiles, and repairing a couple of broken sash windows! It was my first time repairing sash windows so I thought I'd display this job.

Part of window showing sash cable, blue sky and houses visible.

corner of window sash chord hanging down.

These are the photos I received of the defunct window. The most common malfunction with sash windows is failure of the weighting system. This is a system of chords and weights, housed mostly out of sight, within the box-frame. Once this system has failed, the window will no longer remain in an open position. For the user, this can range from a mild inconvenience, to a personal danger, depending on circumstances. It could mean a lack of ventilation, or an impediment to escape in the event of a fire.

In this instance the chords attaching the window to the weight had torn through; so I ordered some new sash rope from Screwfix. Screwfix took so long to get the chord, and I found it in stock at a Jewsons near the job, so I purchased it there instead. If you have sash windows, you can see this chord either side of the window frame, above the lower leaf of the window.

video demonstrating sash chord re-thread

I tried to thread the sash chord directly, and it kept getting lost in the frame somewhere.

Eventually I realized I would have to thread the chord with something less rigid that would navigate through the housing easily. I borrowed this old shoelace from the tenant's son. Once the chord is threaded through it must be secured to the weights inside the box frame, and to the sides of the window leaf. To do this we have to open the box frame; after removing the window bead that secures the window leaf in its run, and the window leaf itself. A crucial part of the process is making sure that the weight remains suspended within the housing, if the weight touches the bottom of the housing, it will no longer present a counterbalance to the window pane. Therefore the chord length is determined so that once the window is fully open, the weight in the box section hovers 20 mm or so from the bottom of the weight housing. Once this is calculated, an allowance is added on to allow the chord to be fixed to the rebates in the side of the sash window leaf frame. This is traditionally done using short clout nails and it is tricky. I performed all these calculations and successfully repaired the windiow:

This is the final result of the reapair, the chords have been replaced and the window is operational.

It was an easy fix, more a matter of being patient and following procedure than anything else. I much prefer fixing these traditional style sash windows. More modern sash windows use spiral balances to counterbalance the window panes. The process of repairing them is actually less complicated, yet it is more specialised, with more expensive components and specialised tools.

I hope you enjoyed this exploration of a common failure in sash windows, and found it informative and useful.

Regards,

Tom,

E.H.S.