Window Woman guides
How to date your windows
Pane patterns, glazing bar profiles and small details like horns can tell you roughly when a window was made. Treat these as guides rather than rules: regional and rural buildings often lagged behind fashion.
Late 17th to early 18th century
Thick glazing bars, small panes, and frames often set close to the face of the wall.
Georgian, c.1714–1830
Typically six-over-six panes, with glazing bars becoming finer and more elegant as the century went on. Building regulations in London pushed frames back behind the brick face, and the fashion spread.
Regency and early Victorian
Look for margin lights: narrow panes around the edges of the sash, sometimes in coloured glass.
Mid to late Victorian
The glass tax was abolished in 1845, and larger, cheaper sheet glass followed. Two-over-two and one-over-one panes become common, and horns appear on the upper sash to strengthen joints carrying the heavier glass.
Edwardian
Often small panes in the upper sash over a single large pane below. Arts & Crafts influence brings casements and leaded lights back into fashion.
Glazing bar profiles
- Ovolo: a rounded quarter-circle moulding, typical of the Georgian period.
- Lamb's tongue: a deeper, more elongated profile, typical of the Victorian period.
- Astragal and hollow: a refined profile found on finer Georgian and Regency work.
A note on glazing bars
- Stick-on or “fake” glazing bars rarely look right and are generally unacceptable on listed buildings
- Conservation officers expect true through-bars that genuinely divide the glass
More guides
These guides are general information for England and don't replace advice specific to your property or your local planning authority.