Georgian Sash Windows Cost

What Georgian 6-over-6 sash windows cost, how glazing bar authenticity affects price, and when listed buildings require true divided lights.

Last reviewed: 2026-07-20 • 5 min read • Verified against 4 heritage joinery quotes

Georgian Sash Window Pricing by Glazing Bar Type

The glazing bar pattern defines Georgian sash windows (typically 6-over-6, sometimes 8-over-8 or 12-over-12 on grand townhouses). How you achieve the bar pattern affects cost dramatically.

Surface-bonded bars: Timber or UPVC bars glued to the glass surface. Cheapest option but looks wrong (thick 20-25mm bars vs authentic 12-15mm). Rejected by listed building consent.

Through-glass bars: Bars inserted between two panes of a sealed double glazed unit. Better appearance than surface-bonded (bars sit inside the glass cavity) but still thicker than authentic Georgian muntins. Sometimes accepted for Grade II listed buildings on rear elevations.

True divided lights: Each sash has 6 individual small panes separated by slim 12-15mm timber glazing bars. Authentic Georgian method. Required for listed buildings and strict conservation areas. Can use modern slim double glazing (two 3mm panes per opening = 6mm per pane) or traditional single glazing with putty.

Why Glazing Bar Authenticity Costs More

True divided light sashes require skilled joinery and significantly more labour than a single-pane sash with bonded bars.

The extra labour adds £150-£400 per window for true divided lights. The payoff: authentic 12-15mm glazing bar width matches original Georgian proportions. Bonded bars are 20-25mm wide (to hide the adhesive joint and provide stiffness) and look noticeably chunky.

Listed Building Requirements for Georgian Sash Windows

Listed Georgian buildings (pre-1837, most are Grade II or II*) face strict requirements on sash window replacement. Conservation officers prioritise maintaining the original slender glazing bar proportions that define Georgian architecture.

What Gets Approved:

• True divided lights with 12-15mm glazing bars matching original pattern (usually 6-over-6, sometimes 3-over-3 or 8-over-8)
• Slim double glazing (two 3mm panes = 6mm total per opening, achieves U 1.8-2.0 W/m²K)
• Hardwood construction (oak preferred, sometimes accoya accepted for rear elevations)
• Putty glazing on external face (not modern gaskets or beads)
• Traditional cords and weights (spiral balances often rejected as non-authentic)

What Gets Rejected:

• Surface-bonded Georgian bars (wrong proportions, visually obvious)
• UPVC sashes (wrong material for pre-1837 building)
• Standard 24mm double glazing (too thick, changes sightlines)
• Modern sash fasteners (must use traditional Brighton or fitch pattern)

Listed building consent costs £100-£300 per application. Get consent before ordering windows. Many joinery firms won't quote for listed work without consent already granted.

Georgian Window Size and Cost

Georgian sash windows vary in size by house type. Grand townhouses have larger sashes (more expensive), workers' cottages have smaller sashes.

All prices are hardwood with true divided lights and slim double glazing, fully installed. Add £300-£600 per window for heritage crown glass or hand-blown cylinder glass (sometimes required for Grade I or II* properties).

Georgian Sash Window Patterns

Not all Georgian sashes are 6-over-6. The pattern varied by period and social class of the building.

• 6-over-6: Most common Georgian pattern (1750-1837). Upper and lower sash each divided into 6 panes (3 wide × 2 high).
• 8-over-8: Grand houses (1760-1810). Each sash has 8 panes (4 wide × 2 high). Adds £100-£200 per window versus 6-over-6 (more glazing bars, more labour).
• 12-over-12: Very grand townhouses (1770-1800). Each sash has 12 panes (4 wide × 3 high). Adds £200-£350 per window versus 6-over-6.
• 3-over-3 or 2-over-2: Late Georgian (1810-1830s) as glass technology improved and larger panes became affordable. Saves £60-£120 per window versus 6-over-6 (fewer glazing bars).

Check photos of your street from 1900-1920 (before most replacements happened) to identify the original pattern. Local studies library or heritage centre usually holds these.

Georgian Sash Restoration vs Replacement Cost

Many Georgian properties still have original 18th or early 19th century sash windows. If the frames are fundamentally sound, restoration costs less than replacement and preserves the historical fabric.

For full details on restoration pricing, see our sash window refurbishment cost guide.

Sources

Pricing verified against:

• London Crown Glass heritage sash window quotes (true divided lights, Jan 2026)
• The Sash Window Workshop Georgian sash pricing (trade list, Dec 2025)
• Historic England technical guidance on Georgian glazing bar proportions (2024)
• MyBuilder heritage joinery quotes for listed Georgian properties (2025-2026)