Windows
Timber sash windows
We design, make and install bespoke timber sash windows for period homes across London and the Home Counties. Each window is made to your property's exact profiles — box sash or spiral-balance, in Georgian, Victorian or Edwardian proportions — combining authentic appearance with modern glazing and draught-proofing.
The timber sash window is the defining feature of London's Georgian, Victorian and Edwardian streets. Its vertical sliding sashes, slender glazing bars and carefully proportioned panes give a period façade its character — which is exactly why a replacement has to be right.
We make every sash window to order, matching the mouldings, glazing-bar widths, horns and meeting rails of your existing windows. Whether you want the low-maintenance convenience of a concealed spiral balance or the authentic operation of traditional weights and cords, the window is built around your home rather than pulled from a catalogue.
Behind the traditional appearance sits modern performance: slim double or vacuum glazing, microporous factory-applied paint, and discreet draught-proofing that makes a period room genuinely comfortable.
A sash window should look as though it has always been there — and work better than the one it replaced.
What matters
Designed around the rules for your home
Made to your home's proportions
Georgian six-over-six, Victorian two-over-two with horns, or Edwardian three-over-one — we match the glazing pattern and sightlines to your property's era so the windows read as original.
Your choice of mechanism
Our Modern range uses a concealed spiral balance for smooth, low-maintenance operation. Our Classic and Historic ranges use traditional weights and cords for authentic period feel — ideal where appearance and operation both matter.
Performance without compromise
Slim double and vacuum glazing options reach whole-window U-values as low as 0.8 W/m²K, with timber-masked or true glazing bars preserving the classic look.
Specification
The detail, documented
Specification options for timber sash windows. Final specification is confirmed at survey and tailored to your property and conservation requirements.
Glazing options
| Single glazed | 6mm toughened glazing with a solid through 'true bar' up to 24mm and putty-imitation external beads — for the most stringent heritage settings |
|---|---|
| Slim double glazed | 12mm unit (4–4–4, argon, low-E) giving a whole-window U-value of 1.9–2.2; or 14mm unit (4–6–4, argon, low-E) giving 1.6–1.8 |
| Vacuum glazed | 7.8mm high-spec vacuum glazing giving a whole-window U-value of 0.8–1.0 — the slimmest sightline with the highest performance |
| Timber-masked glazing bars (20mm) | Our most popular bar. Slim 20mm bars in matching timber, factory-finished with the window — ideal for Georgian, Victorian and Edwardian properties |
| True glazing bars (up to 24mm) | Solid through 'true bars' up to 24mm wide (not stick-on), with putty-line finish |
| Leaded lights | Traditional leaded-light glazing in diamond or rectangular (square) patterns — ideal for period, heritage and conservation properties |
Timber species
| Engineered redwood pine | With hardwood sill — our most popular option, chosen for stability and value |
|---|---|
| Full hardwood meranti | A durable hardwood throughout |
| Accoya® | Modified timber with exceptional stability and longevity |
| European oak | A premium, characterful hardwood |
| Certification | FSC® certified timber |
Joinery & sash mechanism
| Construction | Traditionally mortise-and-tenon jointed, manufactured to order |
|---|---|
| Modern range | Spiral-balanced mechanism with concealed balances — smooth operation, minimal maintenance |
| Classic range | Traditional weights and cords with steel or lead counterweights, for authentic period operation |
| Historic range | Traditional weights and cords for listed and conservation properties — suitable for vacuum glazing and traditional glazing-bar profiles |
Finish
| Paint system | Factory spray-finished before delivery; microporous system that lets the timber breathe |
|---|---|
| Colours | Single or dual colour, with a wide choice of RAL colours. We can also colour-match heritage brands such as Little Greene and Farrow & Ball |
| Coating warranty | 3 years on the factory-applied paint finish, subject to the recommended maintenance; recoating intervals depend on exposure and location |
Guarantee
| Component | Warranty |
|---|---|
| Timber frame | 8 years |
| Glass & sealed units | 3 years |
| Hardware & ironmongery | 5 years |
| Paint finish | 3 years |
| Conditions | Timber and paint guarantees are subject to the recommended maintenance schedule. Guarantees cover manufacturing defects, not damage, neglect or normal wear. |
How it works
From first survey to aftercare
- 01
Initial quotation
We provide an initial quotation within 1–3 days of your enquiry.
- 02
Site survey
Within 1–2 weeks we measure and document the openings on site, recording profiles, sightlines and any conservation status.
- 03
Drawings & approval
We produce production drawings and a specification for your approval — and to support any planning or listed building consent.
- 04
Manufacture
Once your specification is approved, each window is crafted to your approved specification. Typically 5–8 weeks; 7–12 weeks for larger or bespoke conservation work.
- 05
Installation
Our fitting teams install with minimal disruption — typically 1–5 days depending on project size.
Questions
Listed building windows: your questions answered
What is a box sash window?
A box sash window has two vertically sliding sashes counterbalanced by weights concealed within a hollow 'box' frame on each side. It is the traditional London sash window, used throughout the Georgian, Victorian and Edwardian periods. We make both traditional weighted box sashes and modern spiral-balance versions.
Should I choose spiral balances or traditional weights and cords?
Both work beautifully. Spiral balances (our Modern range) are concealed, smooth and low-maintenance. Traditional weights and cords (our Classic and Historic ranges) give the authentic operation and are usually preferred — sometimes required — for listed buildings and conservation areas. We advise based on your property and any planning considerations.
Can sash windows be double glazed?
Yes. Our slim double-glazed units (from a 12mm argon-filled, low-E build-up) and vacuum glazing achieve whole-window U-values as low as 0.8 W/m²K while keeping slim sightlines and authentic glazing bars. In the most sensitive heritage settings, single-glazed options with true bars are also available.
Will new sash windows match my period property?
That is the aim. We match glazing patterns, bar widths, horns, meeting rails and sightlines to your home's era — Georgian, Victorian or Edwardian — so the windows look authentic while operating better than the originals.
Which areas do you cover?
We work across London and the Home Counties, including Surrey, Kent, Essex, Hertfordshire and Buckinghamshire.
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Discuss your project
Tell us about your property and we’ll advise on the most appropriate, consent-ready specification.
01527 590 776