Georgian Style Sash Windows: Specifying Proportion, Detail and Authenticity

• 23 April 2026|
• News

When specifying Georgian style sash windows, it’s important to consider proportion, detail and authenticity. For architects, developers and housebuilders working on period properties or new builds that draw from Georgian architecture, getting the sightlines, glazing bars and frame detailing right is what separates a well-considered scheme from a generic one.

This blog explores how to specify Georgian style sash windows today, including how modern thermal and acoustic requirements can be met without compromising traditional aesthetics.

What are key characteristics of Georgian sash windows?

In a nutshell

Georgian sash windows rely on slim sightlines, true astragal bars and carefully proportioned glazing to capture period authenticity. Modern timber sash windows from Lomax + Wood combine this detailing with double glazing, weather-stripping and U-values as low as 1.1 W/m²K, making them suitable for conservation areas, listed buildings and contemporary projects alike.

A deeper dive into the Georgian window style

The Georgian period (1714 to 1830) introduced a type of window that remains one of the most recognisable features of British architecture. The classic Georgian sash window design featured a six-over-six configuration: two sashes, each divided into six smaller panes of glass by slim glazing bars. This layout was a practical response to the glassmaking technology of the Georgian era, where producing larger panes was expensive and technically difficult.

As manufacturing advanced, Victorian sash windows began to feature fewer, larger panes, often in a two-over-two or one-over-one configuration. Edwardian sash windows often returned to multi-pane upper sashes paired with a plain lower sash, creating a hybrid style.

What defines authentic Georgian style windows

For architects working on Georgian designs, the following specification details matter most:

• Proportion: Traditional Georgian windows are taller than they are wide, typically with a vertical emphasis of around 2:1. Window panes within each sash should be close to square.
• Glazing bars: True astragal bars, usually 18 to 22mm wide with an ovolo or lamb’s tongue profile, create authentic shadow lines. Stick-on bars rarely convince the eye.
• Sightlines: Slim meeting rails, narrow stiles and a deep bottom rail on the lower sash are essential to the Georgian style
• Frame detail: A recessed box frame, parting bead and staff bead all contribute to the depth and character of traditional Georgian windows.

Can you meet modern performance standards with traditional sash windows?

The challenge for specifiers today is matching Georgian style with contemporary performance. Building regulations in England & Wales require evidence of energy efficiency, security and weather performance, even in conservation areas where visual sensitivity is paramount.

At Lomax + Wood, our timber sash windows are engineered to deliver:

• U-values as low as 1.1 W/m²K with factory-fitted double glazing
• Noise reduction of 36dB as standard, rising to 42dB with the acoustic+ upgrade
• PAS 24 (2016) security certification, Part Q compliant
• Weather testing to BS6375 part 1: Air Class 4, Wind Class C5, Water Class 7A

For listed buildings where double glazing is not permitted, single glazed sash windows with vacuum sealed unit options provide a solution that satisfies conservation officers while offering improved thermal performance over traditional single glass panes.

The Lomax + Wood range of timber sash windows

We offer three principal styles of sash window, each suited to different project types:

Timber box sash windows

Our flagship option for period property restoration and high-specification new builds. Traditional cord and weight operation, authentic detailing and U-values as low as 1.1 W/m²K.

Spring balance sash windows

A more economical made-to-order solution often specified by developers and housebuilders where a flush reveal has been detailed. Factory double glazed and fully weather-stripped, delivering historically accurate appearance at a competitive price point.

Single glazed sash windows

Designed for listed buildings and heritage projects where modern materials and double glazing are restricted. Putty glazed with true glazing bars to meet heritage and conservation officer requirements.

All windows are made using responsibly sourced FSC® or PEFC certified timber including Engineered Redwood, Hardwood, Oak or Accoya, with custom sizing and various colour finishes available. Each product is made to order, allowing us to meet specific architectural requirements while incorporating practical features such as secure locking systems, durable finishes, and appropriate glazing options to improve comfort and efficiency.

Specifying for conservation areas and listed buildings

Projects within conservation areas often require that new windows match the design, material and detail of the original. Our expert team works closely with architects and conservation officers to match existing profiles, sightlines and the number of panes, delivering new sash windows that sit comfortably alongside surviving originals.

Compared with uPVC sash windows, timber windows offer deeper reveals, slimmer glazing bars and a finish that ages gracefully. Timber remains the material of choice for period property work, and over the long run offers better repairability than composite alternatives.

Common specification questions

Can Georgian sash windows be made with double glazing?

Yes. Our timber sash windows are factory double glazed as standard, with slim-profile units available to preserve traditional glazing bar widths.

What about bay windows?

We produce sash windows in bay configurations, matching the style of window to the existing architecture.

How do they compare with casement windows for Georgian properties?

Sash windows are the correct historical choice for most Georgian buildings. Casement windows are more typical of earlier or rural vernacular architecture.

Can finishes be matched to a specific RAL or heritage colour?

Yes. Our timber products are available in single colour, dual colour and natural stained finishes, with RAL and heritage colour matches available.

Get a quote for Georgian style sash windows: contact Lomax + Wood

If you are specifying Georgian style sash windows for a conservation project, a listed building or a new build drawing on Georgian architecture, our team is here to help. The quality of our products, combined with our attention to detail and customer service, has made Lomax + Wood a trusted supplier to architects, developers and homeowners across the UK.

To discuss your project or request a free quote: Complete our online contact form or call us  on 01277 353857.