★★★★★
“Professional service and excellent product. OBSW were able to specify windows that other companies said were impossible.”Edward Christie
Replacement timber sash windows · Made in Britain
Replacement Timber Sash Windows
Replace what is failing. Keep what makes the house beautiful.
Made-to-measure replacement sashes and complete timber sash windows designed around the existing architecture, with modern glazing, draught control and security where appropriate.
- Matched to original proportions and character
- Replacement sashes or complete windows
- Modern glazing and security options
- 50-year timber-frame guarantee
Get My Quote →
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
Replace only what needs replacing — and get the details right.
A replacement project should start with the building, not a catalogue. We look at the proportions, existing boxes, frames, mouldings and condition so the right level of replacement can be specified.
- Matched to original proportions and character
- Replacement sashes or complete windows
- Modern glazing and security options
- 50-year timber-frame guarantee
Why Box Sash
A replacement should not advertise that it has been replaced.
The aim is a window that belongs to the façade. Sightlines, bars, horns, mouldings and finish are considered before manufacture so the result feels architectural rather than generic.
- 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
Need to replace tired sash windows without changing the character of the house?
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.