Window Woman guides
Historic window types
Know what you have before you decide what to do. Many old houses have several window types from different periods, and rear and attic windows are often older than those at the front.
Vertical sliding sash with weights and pulleys
The classic British window from the late 17th century onwards. Two sashes slide up and down in a hollow “box” frame, each balanced by cast-iron or lead weights on cords that run over pulleys and hang hidden inside the box.
Box sashes are found in Georgian, Regency, Victorian and Edwardian houses. With care they last for centuries, they can be re-corded and serviced easily, and good draught-proofing can transform their performance. See the anatomy of a box sash for every part named.
Vertical sliding sash with concealed spiral balances
A 20th-century development. Spring-loaded spiral balances replace the weights, so the frame can be solid and slimmer. They're common in later replacements and in “heritage-style” new windows.
From a distance they can look similar, but the frame depth and detailing differ. In a listed building that still has weighted box sashes, they are rarely an acceptable substitute.
Yorkshire sliding sash
The sashes slide sideways rather than up and down, usually with one fixed and one sliding sash, and there are no weights or pulleys. This is a vernacular window of northern England, found in cottages, farmhouses and workers' housing, often on upper floors and rear elevations.
Surviving examples are increasingly rare and well worth protecting.
Side-hung casement
Hinged at the side and opening like a door, the casement is the oldest type of opening window. Casements are common in vernacular, rural and Arts & Crafts buildings. Traditional casements sit flush with their frame; see flush vs storm-proof casements for why that matters.
Leaded lights
Small panes (quarries) held in strips of lead (cames), sometimes set in iron casements. You'll see them in earlier vernacular buildings, churches, and Arts & Crafts and Tudor-revival houses.
Steel windows
Slender metal windows, such as those made by Crittall, were popular from around 1900 and especially in the 1920s and 30s. They are an important part of the character of many interwar homes.
Fixed lights and special shapes
Fanlights and top lights are glazed panels that don't open, often above doors or as part of a larger window. Bays, oriels, Venetian windows (three lights with an arched centre), Gothic lancets and semicircular windows are usually key architectural features of a house and deserve particular care.
Before any work
- Photograph every window, inside and out
- Note which type each one is, and whether it looks original or a later replacement
- Don't assume the front windows are the oldest
More guides
These guides are general information for England and don't replace advice specific to your property or your local planning authority.