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Georgian windows with their elegant glazing bars present unique challenges. Learn how to add secondary glazing while respecting the period aesthetic.
Georgian windows are among the most elegant in British architectural history. Their slim glazing bars dividing multiple small panes create a distinctive character that defines the period—from grand townhouses to modest terraces. But this very elegance creates challenges when you want to improve thermal and acoustic performance.
Georgian windows (roughly 1714-1830) have distinctive characteristics:
Six-over-six (twelve panes total) is classic Georgian. Earlier examples might be twelve-over-twelve; later Georgian often used six-over-six or even two-over-two as glass technology improved.
The meeting rails and glazing bars are remarkably thin—often just 20-25mm wide. This allowed maximum light while supporting the small panes that glass technology of the time could produce.
Original Georgian glass has subtle waves and imperfections that catch the light. This character is impossible to replicate with modern float glass.
Georgian windows follow classical proportions. The pane dimensions, bar widths, and sash sizes were carefully considered. Alterations that disrupt these proportions look wrong, even if viewers can't articulate why.
Adding secondary glazing to Georgian windows requires sensitivity to these characteristics:
Should the secondary glazing replicate the Georgian pane grid, or use a single large pane?
Advantages:
Disadvantages:
Advantages:
Disadvantages:
For most Georgian properties, we recommend aligned single-pane secondary glazing with careful attention to frame positioning:
This approach
For expert secondary glazing advice and free consultations for listed buildings in London, contact Secondary Glazing Specialist on 020 7060 1572.
James Whitfield
Conservation Planning Advisor
Georgian windows are among the most elegant in British architectural history. Their slim glazing bars dividing multiple small panes create a distinctive character that defines the period—from grand townhouses to modest terraces. But this very elegance creates challenges when you want to improve thermal and acoustic performance.
Georgian windows (roughly 1714-1830) have distinctive characteristics:
Six-over-six (twelve panes total) is classic Georgian. Earlier examples might be twelve-over-twelve; later Georgian often used six-over-six or even two-over-two as glass technology improved.
The meeting rails and glazing bars are remarkably thin—often just 20-25mm wide. This allowed maximum light while supporting the small panes that glass technology of the time could produce.
Original Georgian glass has subtle waves and imperfections that catch the light. This character is impossible to replicate with modern float glass.
Georgian windows follow classical proportions. The pane dimensions, bar widths, and sash sizes were carefully considered. Alterations that disrupt these proportions look wrong, even if viewers can't articulate why.
Adding secondary glazing to Georgian windows requires sensitivity to these characteristics:
Should the secondary glazing replicate the Georgian pane grid, or use a single large pane?
Advantages:
Disadvantages:
Advantages:
Disadvantages:
For most Georgian properties, we recommend aligned single-pane secondary glazing with careful attention to frame positioning:
This approach maintains the Georgian character while maximising acoustic and thermal performance. The secondary glazing becomes a neutral layer behind the detailed original.
For Grade I listed buildings or where conservation officers specifically request it, we can provide grid-matched solutions with glazing bars aligned to the original pattern.
Georgian reveals are often deep (150-200mm), providing excellent space for secondary glazing. This depth allows optimal air gaps for acoustic performance.
Many Georgian properties have internal shutters housed in deep boxes either side of the window. Secondary glazing must be designed to allow shutter operation:
Georgian sash windows slide vertically using counterweights. Secondary glazing should not interfere with this operation. We typically recommend vertical-sliding secondary units to match the original mechanism.
Many Georgian properties are listed:
Buildings of exceptional interest. Secondary glazing may require Listed Building Consent. We can prepare detailed specifications to support applications. Grid-matched solutions often preferred.
Particularly important buildings. Similar considerations to Grade I—early consultation with conservation officer recommended.
Buildings of special interest. Internal secondary glazing typically doesn't require consent as it doesn't affect external character, but check with your local authority.
Georgian streets are often in conservation areas. Secondary glazing is usually straightforward as it's internal and invisible from outside.
For the most sympathetic installations:
Match frame colour to interior joinery—often off-white, cream, or heritage colours. Avoid stark white or obviously modern metallic finishes.
Where handles or fasteners are visible, specify traditional designs. Modern lever handles look incongruous against Georgian windows.
While secondary glazing uses modern float glass for performance, we can specify slightly textured glass if a softer appearance is desired. This marginally reduces clarity but may better complement original crown glass.
Georgian windows benefit significantly from secondary glazing:
The deep reveals characteristic of Georgian architecture actually benefit acoustic performance—they provide space for larger air gaps.
Grade II listed Georgian townhouse in Camden:
Georgian window secondary glazing typically costs:
For a typical Georgian townhouse (10-15 windows), expect £10,000-£20,000 for comprehensive treatment.
Georgian windows require specialist understanding. Request a survey to discuss your property's specific requirements and see examples of our Georgian installations.
Call 020 7060 1572 to speak with a heritage glazing specialist.
London's leading secondary glazing specialists for Grade I, Grade II, and Conservation Area properties. Every project begins with a complimentary heritage survey.
