Walk down any Georgian terrace in Bath, Winchester or Salisbury and the windows tell you everything about the building behind them.
Tall proportions. Fine glazing bars. A sense of order that runs from the ground floor right up to the attic.
Georgian windows are one of the most recognisable features in British architecture. They also happen to be one of the most misunderstood, especially when it comes to replacement.
At Tailored Wood, we spend our working lives inside this detail. We restore, replicate and replace Georgian sash windows across listed buildings and conservation areas throughout Hampshire, Wiltshire, Dorset and the wider South of England. This guide draws on that hands-on experience.
What do Georgian windows look like?
Georgian windows are almost always timber sliding sash windows, built with a strict grid of small panes held in place by slim glazing bars.
The classic layout is six panes over six panes, known as a 6 over 6 sash. Larger or grander properties sometimes used 8 over 8 or 12 over 12 configurations.
The panes are close to square or slightly upright in shape. The glazing bars are slender, with a rounded or ovolo profile. The sashes have no visible horns at the corners.
Windows sit flush or near-flush with the brickwork, and every window on a facade lines up with its neighbours in height and width. Symmetry is the whole point.
If you want one detail to check on your own house, look at the corners of the sash where the top and bottom rails meet the stiles. A plain, horn-free joint points to a genuine Georgian sash or an early replacement. A small projecting horn usually signals a later, Victorian addition.
A short history: why Georgian windows look the way they do
Georgian windows didn’t appear by accident. Every feature responds to a real constraint of the period.
Glass technology set the pane size
Georgian glaziers worked with crown glass, spun by hand into discs and cut into panes. The centre of each disc, the bullion, was too distorted to use. Useable pane sizes stayed small as a result, which is the entire reason for the multi-pane grid.
By the later Georgian period, cylinder glass allowed slightly larger panes. You’ll sometimes see 6 over 9 or asymmetric arrangements on later Georgian buildings for this reason.
The window tax shaped the elevation
The window tax, introduced in 1696 and still active through most of the Georgian era, charged homeowners by the number of windows in a property. Architects responded by designing facades with fewer, larger, beautifully proportioned windows rather than many small ones.
This is why Georgian elevations feel so composed. Every window earned its place.
Classical proportion governed everything else
Georgian architecture followed classical rules borrowed from Palladio and the Italian Renaissance. Window height to width ratios, the spacing between openings, and the reduction in window size as you move up a facade all follow set proportions rather than personal taste.
A ground floor window on a Georgian townhouse is typically taller than the window directly above it. This graduated scaling, tallest at the piano nobile and progressively smaller towards the attic, is a genuine Georgian signature and one we check for on every restoration project.
Key features of an authentic Georgian sash window
When we assess a Georgian window, whether for restoration or a period-correct replacement, we’re looking at several details together. No single feature makes a window Georgian on its own.
Glazing bar profile and thickness
Georgian glazing bars are slim, usually an ovolo or lamb’s tongue moulding on the room-facing side. They sit noticeably thinner than the chunkier bars introduced later in the Victorian period, when plate glass allowed wider panes and heavier bars.
Getting this profile right, or wrong, is the difference between a window that reads as genuinely Georgian and one that looks like a generic period-style product.
Pane arrangement
6 over 6 is the benchmark, but pane count should always match the age and status of the specific building rather than a general rule. Grander Georgian townhouses often carried 8 over 8 or even 12 over 12 arrangements on principal rooms, with simpler layouts on upper floors and service windows.
No horns
Horns, the small curved projections at the top corners of a sash, are a Victorian innovation designed to add strength once plate glass made sashes heavier. Genuine Georgian sashes are horn-free.
Adding horns to a Georgian-style window is one of the most common period-accuracy mistakes we see, and one we deliberately avoid when replicating original details.
Box frames and weights
Georgian sash windows run on a traditional box frame, with cast iron or lead weights hung on cords inside boxed jambs to counterbalance the sashes. This is a mechanical system as much as a joinery one, and it needs to be built with the correct box depth and pulley position to work smoothly for decades.
Flush or near-flush setting
Georgian windows were typically set close to the front face of the brickwork, later regulations pushed sashes back within the reveal for fire safety reasons on some properties. Knowing which rule applied to a given building, and when, matters for both authenticity and building control compliance.
Glass character
Original Georgian glass has a very slight waviness and imperfection, a result of the crown glass process. Reproduction restoration glass replicates this character, giving a finished window subtle depth rather than the flat, dead-clear look of standard modern float glass.
What goes into a period-correct Georgian replacement
Replacing a Georgian sash window properly is a research task as much as a manufacturing one. Here’s how we approach it.
Survey and record the original detail
Before cutting any timber, we measure and photograph the surviving windows on the property, including glazing bar width, moulding profile, box depth and pane layout. On terraces and listed buildings, we’ll often check neighbouring properties too, since Georgian developments were usually built to a single pattern book.
Match timber species and jointing method
Georgian sashes were built in slow-grown softwood or oak, jointed with mortise and tenon construction and pegged rather than screwed. We replicate these joints in-house, so the new window behaves and ages the way the original one did.
Recreate the correct glazing bars
We cut glazing bars to match the original profile and thickness rather than fitting a standard off-the-shelf bar. On conservation area and listed building projects, this level of detail is frequently what planning officers are checking for.
Specify glass with care
Where a project calls for improved thermal performance, we fit slimline double glazing or vacuum insulated glass units within the traditional bar structure, keeping the external sightlines identical to the original single-glazed window. The glazing choice never overrides the period detail.
Finish with the right paint and putty
Georgian sashes were finished in linseed putty and painted in flat, muted colours rather than the brighter palette that arrived later. Getting the finish right completes the authenticity of the window, both up close and from the street.
Restoration or replacement: how to decide
Not every Georgian window needs replacing. If the timber is sound and the issue is draughts, sticking sashes or worn cords, restoration usually delivers a better outcome for your budget and for the building’s fabric.
Replacement makes sense where:
- Rot has reached the point of no economical repair
- The existing windows are later, poorly matched replacements rather than originals
- A full set of new windows is being made to match a documented period design
Listed buildings and conservation areas add another layer. Replacing a Georgian window, even with an identical copy, usually requires Listed Building Consent. We handle this process regularly and can guide you through what your local authority will expect to see.
Talk to Tailored Wood about your Georgian windows
We’ve spent years working on Georgian sash windows across listed buildings and conservation areas throughout Hampshire and the South of England. Every window we make is produced entirely in-house, from survey through to final installation, so the glazing bar profile, pane proportions and finish all match what your building actually needs.
If you’re weighing up restoration against replacement, or you want windows built to a genuinely period-correct Georgian specification, get in touch for a free quote.
A large part of his role involves guiding clients through planning and listed building applications, helping them meet conservation requirements while protecting the character of their property. His specialist knowledge covers traditional box sash windows, casements, slim heritage glazing systems and high-performance timber solutions that balance authenticity with modern standards.
Jakub takes a hands-on approach built on leadership, attention to detail and accountability, giving clients clear direction, practical solutions and full confidence from start to finish.
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