Retain the original box. Upgrade the sashes
Retrofit double glazing in West London
If the original box frame remains sound, complete window replacement may not be necessary. New made-to-measure hardwood sashes with slim double glazing can often be fitted into the existing frame, improving performance while retaining more of the original joinery.
When this service fits
Is the existing box frame suitable?
Where the existing box frame is sound, replacing it may add unnecessary cost and disruption. A retrofit retains the frame while new made-to-measure sashes are fitted, with the existing joinery repaired, prepared and adapted as required.
Common signs
How the work is approached
Survey, scope, then do the work properly.
- 1
Survey the existing profiles
We measure the openings, glazing bars, horns and mouldings that define the character of the existing window.
- 2
Make the new sashes
Hardwood sashes are made to the agreed design, proportions and glazing specification.
- 3
Restore the frame and install
The existing frame is repaired and prepared before the new sashes are balanced, sealed and fitted.
Typical scope
What the quotation can include.
The final scope is always based on the survey and set out in writing.
- Survey and measurement of the existing box frame and sash profiles
- Repair and preparation of the existing frame
- New made-to-measure hardwood sashes
- Agreed double-glazed units and glazing specification
- New or adapted cords, weights and hardware as required
- Installation, adjustment and final checks
Completed by Stile
Recent double-glazed retrofit projects.
These are completed STILE projects. The exact retrofit scope for each property is established after the existing windows and box frames have been surveyed.
Retrofit glazing
Double-glazed French doors
Questions about double-glazed retrofit
The details worth understanding first.
Can every sash window take double glazing?
No. The frame condition, sash dimensions, glazing-bar design and any planning constraints all matter. A survey is needed before recommending the right specification.
Will the glazing bars look too thick?
The aim is to keep the new profiles proportionate to the originals. The available glass unit and the existing design determine how closely very fine historic bars can be replicated.
Related services
Draught-proofing
Discreet sealing for original timber windows and doors, combined with a full service of the moving parts.
View serviceComplete renewal
Bespoke hardwood box frames and sashes made for the opening when renewal is the better long-term investment.
View serviceRestoration
Joinery repair, preparation, servicing and redecoration for windows that need more than a quick fix.
View servicePlan the decision
Guides to help you plan the work.
Completed evidence
Case studies with the work explained
Free, no-obligation quote