New Sashes into Existing Window Frames
New, Double-Glazed, Timber Window Sashes Installed into Existing Window Frames
If your sash window or casement window frames 
are in good condition, we can replace just the moving parts of your timber window (the sashes), allowing for double glazing without replacing the window frame.
High-Quality Performance
We purposely select materials that offer the highest quality performance and durability, meaning that our windows are easy to use, secure, and require minimal maintenance. We are FSC® certified, meaning that the materials used in our windows are sustainably sourced.
Established in 1994, we have 30 years of experience working on a wide range of period properties, including Georgian, Edwardian, and Victorian homes.
What are sashes on a window?
Sashes are the parts of a window that move when you open or close a window. By installing new sashes into existing window frames, you can upgrade to double-glazed sash windows or casement windows without having to also replace the window frame.
This enables you to have more energy-efficient windows at a fraction of the cost of replacement. Installing new sashes also helps minimise disruption and retain the heritage of your traditional home.
HIGH ATTENTION TO DETAIL
We have extensive experience installing new sashes into the existing frames for both timber sash windows and casement windows.
When replacing the moving parts of the window, a high level of attention to detail is required in order to ensure that the new sashes fit and operate smoothly. This means that an exceptional level of attention to detail is required when measuring for the replacement sashes before they are manufactured to fit precisely.
At The Sash Window Workshop, we will always take great care ensuring your existing windows are matched exactly and retain the original style of your home.
Energy Efficiency at a Fraction of the Cost
By replacing just the sashes (moving parts) of the window, you can upgrade to all the benefits of double glazing without having to replace the whole window, helping to keep down the cost.
The new sashes we fit to existing window frames are normally double glazed (unless single glazing is required). We offer a range of glass and paint finishes for your new sashes.
Your windows are draught sealed to help keep your home warm and further improve energy efficiency and soundproofing.
During the installation process, the old sashes are removed before the new sashes are carefully hung in their place. New ironmongery is also fitted to your windows.
Below is a quick walkthrough of The Sash Window Workshop installing new timber sliding sashes into existing window frames:
Accoya: Sustainable, Anti-Rot Timber Windows
For new sashes we recommend using a timber called Accoya, which comes with a 50-year anti-rot guarantee. Accoya is a sustainably sourced, highly durable, and stable wood.
As the installation of new sashes into the existing window frame does not go back to the brickwork, FENSA deems this work as repair work, rather than replacement. This means that a FENSA certificate is not required for this work.
If your windows require full replacement, we can also manufacture and install complete new sash windows and casement windows. If you are not looking to upgrade to double glazing, we also offer a draught-proofing service for timber windows.
Below shows a bay sash window where we installed new
sashes into the existing window frames
BEFORE
DURING
AFTER
Unsure what type of windows you have? Sash windows slide up and/or down to open, whereas casement windows open on hinges, like a door.
OUR NEW SASHES INTO EXISTING WINDOW FRAMES GUARANTEES
50
YEARS
Guarantee
YEARS
Joinery
Guarantee
YEARS
Guarantee
YEARS
Guarantee
5
YEARS
Guarantee
*Maximum Guarantees Shown. Please see our Guarantee and Maintenance documents for further information.