The Window as Period Marker: Sash vs. Casement

Windows and their antique window hardware are some of the most reliable date evidence a house carries, because they change slowly and get replaced reluctantly. The type of window, and the specific fittings that operate it, often tell you more about a building's age than anything on the facade.

The double-hung sash

The double-hung sash window, two panes sliding vertically past each other, dominated American building for two centuries, and its details shifted over time. Early sashes held small panes divided by thick wooden muntins, because large glass was expensive; as glass got cheaper, the panes grew and the muntins thinned, until a late window might be a single large light. The hardware followed: sash locks, lifts, and the weights and pulleys hidden in the frame each changed shape by period, and because they're used constantly and rarely swapped, they survive as original evidence.

The casement

The casement window, hinged at the side and swinging out, tells a different story. Common in early colonial building, largely displaced by the double-hung, then revived in the Tudor and storybook styles of the early twentieth century, the casement comes with its own hardware, the crank-out adjusters, stays, and fasteners that let it open and hold. A casement adjuster is a fairly specific, datable part.

None of this appraises the window; it dates it. But dating is what tells you which hardware belongs and which wandered in.