London Sash and Frame – The Perfect Fit for Box Clever Sash Windows
Case Studies
Client
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Architects
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Contractor
Box Clever Sash Windows
Window Range
Harmony
Box Clever Sash Windows – Bygone Harmony
London Sash and Frame
“Our installation ensures these high-specification sash windows blend seamlessly with the building’s period aesthetic while delivering modern performance."
London Sash & Frame Provided the Perfect Fit for Replacement Arched Timber Sash Windows
The Background
When our Master Installer, Box Clever Sash Windows, were approached by a customer seeking to replace their ageing wooden sash windows, there were several specific requirements—most notably, the unusual arched heads on the original timber frames. Given the period character of the street, the homeowner wanted new sash windows that closely resembled the originals in both style and proportion. Additionally, the new windows needed to be durable, energy-efficient, and provide effective noise reduction, due to the property’s location in the busy district of Chiswick, near the M4 corridor in the West London borough of Hounslow.
There were four main concerns at the outset of the project:
1. Conservation & Planning – The house is located within one of the 29 conservation areas in the London Borough of Hounslow. All work needed to comply with the policies set out by the local authority.
2. Arched Openings – The original windows were arched infills set into curved brick openings, requiring precise and sympathetic replacement.
3. Acoustic Performance – Improved sound insulation was essential to mitigate traffic noise from the nearby motorway.
4. Shutter Preservation & Architectural Details – The original timber windows had elegant internal shutters that needed to be retained and refitted. The property also featured unique, custom-profiled architraves used throughout, which had to be matched seamlessly.
The Bygone Collection Guarantee
The Solution
As long-standing members of the Bygone Master Installer Network and specialists in all aspects of sash window installation, Box Clever Sash Windows confidently recommended the Bygone Harmony range for this project. These premium windows feature an exclusive 39mm GRP slim meeting rail, patented Timberweld® joints, and energy-efficient 24mm argon-filled double glazing—a combination that provides both authentic aesthetics and modern performance.
1. Conservation Compliance
As experts in local conservation and planning regulations, Box Clever confirmed with the local authority that while the property was in a conservation area, it was not subject to additional restrictions. This allowed the windows to be replaced under Permitted Development Rights, which require a similar visual appearance but are material neutral—meaning timber-alternative materials were acceptable in this case.
2. Bespoke Arched Window Installation
To replicate the arched openings, the team utilised the exclusive London Sash & Frame feature—designed and engineered by Masterframe. This bespoke solution was crucial to preserving the property’s traditional appearance while meeting modern standards.
The intricate process involved custom jigs, curved panel shaping, and meticulous hand-finishing and painting. This level of craftsmanship makes the London Sash & Frame product one of the most labour-intensive, but also one of the most visually impressive offerings in the Bygone range—perfectly complementing the original architecture.
3. Acoustic Glazing for Noise Reduction
To combat the road noise, and the general hubbub of a busy London suburb, the front-facing windows were fitted with acoustic glazing. This specification included a 6.8mm laminated glass pane, constructed with two 3mm panes and an internal acoustic interlayer, providing a significant upgrade in noise reduction compared to the original single-glazed windows.
4. Retaining Original Shutters & Matching Architraves
Once the window specifications were agreed, Box Clever used a traditional installation method, fitting timber liners into the window aperture. This not only enhanced thermal insulation but also provided a solid timber base, allowing the original shutters to be refitted perfectly—a detail often overlooked in modern installations.
The home’s unique architrave profiles posed a challenge, as no matching mouldings were available from local stockists or timber yards. Box Clever worked with a timber merchant to design a custom tool that could accurately replicate the original profile—demonstrating their meticulous attention to detail.
This level of craftsmanship is just one reason why Box Clever Sash Windows are trusted members of the Bygone Collection’s Master Installer Network.
“London Sash & Frame windows were the perfect solution to replace ageing wooden sash windows”
Sash Windows for Modern Homes
As sustainability concerns and rising energy costs impact households across the UK, the need for efficient, durable, and aesthetically sympathetic window solutions is greater than ever—especially in period properties like this one, over 100 years old.
The Bygone Harmony window is the most popular product in the Bygone Collection, offering a convincing, low-maintenance alternative to traditional timber sash windows. It provides excellent value while maintaining the look and charm of classic timber designs.
Thanks to its distinctive features—including energy-efficient double glazing and the 39mm GRP meeting rail—the Harmony range is often mistaken for hardwood by those seeing it up close. It’s the ideal solution for homeowners who value traditional aesthetics with modern performance.
