Sash Window Cord Replacement

What Is a Sash Cord?

In a traditional sash window, the upper and lower sashes are connected to counterbalance weights by cords (or chains) that run over pulleys in the frame. These cords allow the sash to slide up and down smoothly and hold its position when open. When a cord breaks, the sash drops, becomes stuck, or will not stay open.

Symptoms of a Broken Cord

• The sash slams shut when you try to open it
• The sash will not stay up — it slides down under its own weight
• You can hear the weight drop inside the frame box when the cord snaps
• The sash sits unevenly or is jammed at an angle
• You are propping the window open with a stick or book (we see this a lot)

Option 1: Replace the Cords (Cheapest)

If the frame and sashes are in good condition, a specialist can remove the sash, open the pocket in the frame, reattach the weight to a new cord, and reassemble. This takes 30–60 minutes per sash. Cost is typically £80–£150 per sash, depending on access and the condition of the pulleys.

This is the right option if your sash windows are otherwise in good condition — the timber is sound, the glass is not misted, and the frames are not rotten.

Option 2: Upgrade to Spiral Balances (Better)

If you are already opening up the frame to replace cords, it may be worth upgrading to spiral balances. These replace the traditional weight-and-cord system with a modern spring mechanism that fits inside the sash channel. Benefits: no more cords to break, smoother operation, and the frame box can be insulated (traditional weight boxes are hollow and draughty).

Cost: £150–£250 per sash including fitting. Our replacement sash windows use spiral balances as standard — they are more reliable and allow for better draught-proofing.

Option 3: Full Window Replacement (Best Long-Term)

If the cords are broken AND the frames show rot, the glass is single-glazed or misted, draughts are a problem, or the windows are over 30 years old — full replacement is the better investment. You solve the cord problem plus every other issue at once, and you get a 10-year warranty.

Our replacement sash windows replicate the exact appearance of traditional sash windows — including horns, moulding profiles, and glazing bars — but with modern spiral balances, double or triple glazing, PAS24 security, and Part L compliant thermal performance. See our 3D configurator for instant pricing.

How to Decide

• Cords only — if the window is less than 15 years old, timber is sound, glass is fine
• Spiral upgrade — if you want a permanent fix and better draught-proofing but the frames are good
• Full replacement — if the window has multiple problems (cords + rot + single glaze + draughts), or if the windows are in a conservation area and you need planning-compliant upgrades

Not sure? Book a free survey. We will inspect the windows and tell you honestly which option makes sense — we do not push replacements when a repair will do.