How Often Should You Change Sash Cords?

Sash windows are a beautiful, decorative, and functional part of many period houses, but their maintenance must intermittently be looked into to keep them in good working condition.

One of the principal elements, though one of the most neglected, is the sash cord, which provides the counterbalancing for sash weights so that the window can glide up and down.

But then, what should be the frequency of changing these cords?

As there is no set life as such, conservation specialists, Historic England included, recommend regular sightings and due replacement to avoid failure until the point of maximum wear and tear.

Below are some guidelines on what you should know based on trade practices and our experience.

What Is the Life of Sash Cords?

Sash cords last for quite some years depending on their material, application, and exposure to environment:

• Every 10-15 years – Regular cotton sash cords, in the case of moderate use openings and closings of windows.
• Every 5 – 10 years – If located in areas of high humidity or used frequently.
• Immediately – When fraying, sagging, or stiffness is observed.

Natural cotton or jute sash cords, more commonly used in the majority of sash windows, tend to weaken over time due to exposure to sunlight, moisture, and friction. They gradually degrade until a sudden snap, causing the sash to drop unexpectedly.

This was exactly the case for one of our customers—her sash window suddenly slammed onto her wrist due to a snapped cord. Thankfully, a passerby helped free her, but it served as a stark reminder of the need for ongoing maintenance. (Read her full story here!)

Old-Style Sash Cords vs. Modern Alternatives

In changing sash cords, a choice must be made between the old materials and modern alternatives.

Traditional Cotton and Jute Sash Cords

They were the standard in Georgian and Victorian homes. These have great historical authenticity, but also some downsides:

✔️ Authentic period look
✔️ Soft and quiet operation
❌ Prone to rot in damp conditions
❌ Can stretch over time, affecting window balance
❌ More susceptible to wear, fraying, and snapping

Historic England advises wherever possible to match original building materials on listed buildings, but today, modern reinforcements can also help preserve those original materials.

Nylon-Reinforced Cotton Cords

A great alternative to traditional cords, these have a hidden synthetic core wrapped in cotton.

✔️ Looks and feels authentic
✔️ Stronger and more resistant to stretching
✔️ Longer lifespan (20+ years)
❌ Slightly more expensive than pure cotton

Synthetic (Nylon/Polyester) Sash Cords

Made to last, modern synthetic cords far outlast cotton and resist decay.

✔️ High tensile strength – supports heavier sashes
✔️ Pre-stretched to prevent sagging over time
✔️ Best for long-term durability
❌ Less period-accurate in historic homes

Good nylon-blended sash cords can last 30 years or more, making them a smart investment if low maintenance is desired.

Sash Chains: Brass or Stainless Steel ( US only )

Sash chains were used in some Victorian and Edwardian properties and are the most durable option, especially for very heavy sash windows.

✔️ Lasts 40 or more years if maintained
✔️ Zero stretch — maintains effective window balance permanently
✔️ Ideal for oversized or heavyweight sashes
❌ Requires pulley adjustment when replacing cords
❌ May be noisier than rope-based cords

If you want to replace sash cords as rarely as possible, then sash chains may be the best long-term investment for your property.

When Do You Know Your Sash Cords Are Due for Replacement?

Watch for these warning signs to prevent accidents:

✅ Difficulty Opening/Closing – Heavy/stiff operation.
✅ Frayed or Brittle Cords – Visible wear and tear.
✅ Uneven Movement – The window tilts or doesn’t stay in position.
✅ Sudden Drop of the Sash – If the window slams shut unexpectedly, the cord has likely snapped.

Should Sash Cords Be Changed During a Full Refurbishment?

Most certainly. If you’re restoring sash windows or retrofitting double glazing, then these are the perfect times to change the sash cords.

✔️ Guarantees smooth operation and safety for years to come
✔️ Eliminates the need for replacement in the near future
✔️ Aids proper balancing with new glazing

We replace old sash cords as part of our sash window refurbishment services to ensure the safe and smooth operation of your newly restored or double-glazed windows.

How Much Will It Cost You If You Wait Too Long?

If you allow a sash cord to break unexpectedly, the consequences may include:

🚨 Injury – A sash window can fall suddenly and cause serious harm.
🚪 Property Damage – A dropped sash may crack the glass or damage the frame.
💰 Higher Costs – Emergency repairs or replacing a damaged window is more expensive than proactive maintenance.

Best Maintenance Practices for Sash Windows

To maximise the life of the sash cords and the window:

🔍 Inspect windows annually for frayed cords or issues with the balance.
🖌️ Repaint exterior sashes every 5-7 years to protect against moisture.
🚫 Do not paint over sash cords or pulleys. This can cause stiffness and subsequent damage.
🛠️ Lubricate pulleys and sliding tracks to allow free movement.
♻️ Sash cords should be replaced uniformly to maintain even tension.

Following these maintenance tips will enable your sash windows to last for decades with fewer issues.

Final Thoughts: When Should You Replace Sash Cords?

There is no definite answer, but based on Historic England guidelines and industry best practices, here’s what we recommend:

✔️ Check the condition of your sash cords annually.
✔️ Replace them proactively every 10-15 years, or more frequently in high-use areas.
✔️ Consider upgrading to nylon-reinforced cords or sash chains for longevity.

If it’s been a while since you last checked your sash cords, now is the time.