Choosing the Right Cord for Your Sash Windows
Choosing the appropriate cord will depend on the type of window, the weight of the sash and whether you're carrying out a repair, restoration or new installation. Material is another consideration, with waxed cotton, pre-stretched nylon and polyester offering different characteristics for traditional and modern applications.
The condition of the existing sash window components should also be considered when carrying out repairs. Worn or damaged pulleys can affect operation and contribute to premature cord wear, so it's worth inspecting the complete counterbalance system before fitting a replacement.
Waxed Cotton, Nylon or Polyester?
Waxed cotton cord is a traditional choice and is particularly well suited to the restoration and refurbishment of period sash windows. It combines a traditional appearance with good flexibility and durability, while the waxed surface helps the cord run smoothly over the pulley.
Pre-stretched nylon cord provides excellent strength and resistance to wear. Its low-stretch characteristics help maintain consistent operation over time, making it a practical choice for replacement work as well as new window manufacture.
Polyester cord is another strong, hard-wearing option with good resistance to stretching and everyday wear. It is suitable for a wide variety of timber sash window applications where durability and reliable long-term operation are important.
What Size Cord Do I Need?
When replacing an existing cord, measuring its diameter is usually the best place to start, particularly if the window was operating correctly before the cord became worn or broken.
The replacement should sit comfortably within the groove of the sash pulley and run freely without binding or slipping. If the original cord is missing, badly worn or you're restoring a window with replacement components, check the pulley groove and the requirements of the cord being considered before selecting a diameter.
For heavier sashes, cord strength is also an important consideration. Check the specification of the individual product to ensure it is suitable for the intended application.
Replacing Cord in a Sash Window
Traditional box sash windows use a counterbalance system in which the moving sash is connected to weights concealed within the window box. The cord runs from the sash over a pulley and down to the weight, allowing the sash to be raised and lowered with considerably less effort.
Over time, the cord can become worn, frayed or broken and require replacement. When replacing it, it's worth inspecting the sash pulleys and weights at the same time to make sure the complete system is in good condition.
For step-by-step instructions, read our How to Replace Sash Window Cord guide.
Sash Weights, Cord and Pulleys
Correctly matching the components of a sash window counterbalance system helps the window move smoothly and remain in the desired position when opened.
Reddiseals supplies a comprehensive range of sash weights, sash pulleys and associated sash window hardware for the manufacture, repair and restoration of traditional timber windows. This makes it easier to source the individual components required for anything from a straightforward cord replacement to a complete sash window refurbishment.
