★★★★★
“Professional service and excellent product. OBSW were able to specify windows that other companies said were impossible.”Edward Christie
Double glazed timber sash windows · Made in Britain
Double Glazed Timber Sash Windows
Warmer, quieter rooms. Traditional sash-window character.
Bespoke timber sash windows designed around the proportions of your home, with modern double glazing, draught control and security built into the specification.
- Argon-filled double glazing options
- Traditional glazing bars, horns and mouldings
- Made-to-measure hardwood construction
- 50-year timber-frame guarantee
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Prefer to speak?01753 858196
Free, no-obligation online quote. A few quick choices, then your details.
Since 1979Specialist timber-window manufacturer & installer
Made in BritainBritish timber joinery
FENSARegistered installation
FSCResponsible timber sourcing
50-year guaranteeTimber-frame reassurance
Customer confidence
Proof from finished projects.
High-value joinery is about the product, the fitting and how the property is treated throughout the work.
★★★★★
“The windows are stunning- excellent quality and the installation was so smooth and straight forward.”Jill Benjoya Miller
Designed around the property
Modern comfort without making the window look modern.
The best upgrade is one you feel more than you see. We keep the traditional sightlines, bars, rails and mouldings that give a sash window its character, while improving glazing, draught control and security.
- Argon-filled double glazing options
- Traditional glazing bars, horns and mouldings
- Made-to-measure hardwood construction
- 50-year timber-frame guarantee
Why Box Sash
If the house deserves better than a generic replacement window.
Period homes need more than a standard frame with decorative bars added afterwards. Box Sash treats the glazing, timber proportions and installation as one product so the finished result feels part of the building.
- 01One specialist companySurvey, specification, manufacture and installation considered together.
- 02Made to measureThe details are specified around the building rather than a standard catalogue frame.
- 03Built for the long term50-year timber-frame guarantee and 10-year glazing guarantee.
A clear route to a quote
Four simple steps.
Start online in around a minute. We use your answers to understand the project before the right next step is agreed.
Tell us what you need
Choose the window type and approximate quantity.
Get your quote started
Add your contact details so the project can be reviewed.
Property-specific advice
We discuss the building, scope and specification.
Manufacture & install
Once agreed, the timber joinery is made and fitted as a Box Sash project.
Free online quote · No obligation
Ready to make the house warmer without losing the sash windows?
Tell us what you are considering. It takes a few quick choices to start the quote, and you can speak to us on 01753 858196 at any point.