What Is a Window Sash?

The glass and framework of a window sash

A window sash is the window glass and the framework around the glass holding it in place. The sash is fitted inside the window frame and may or may not be moveable.

Function

Hung window sashes open by sliding up and down inside a window frame. They can also be permanently fixed in place, and some are made to slide horizontally on a track inside the window frame.

Types

Window sashes are composed of one or more panes of glass within a framework. Older windows typically have two or four glass panes in each sash, while more modern windows often have just one pane.

History

Very old windows have multiple glass panes in each sash because small pieces of glass were easier to produce and less expensive to buy. Sashes with fewer panes became more common in houses built after the Civil War.

Features

Old hung window sashes move up and down by a system composed of a pulley, cord and counterweight within the window frame. More modern windows use a spring system.

Construction Materials

Wood is a common material in window sashes, but many modern windows are also constructed of vinyl, PVC, fiberglass or aluminum, all of which require less maintenance than wood.

References

• Old Home Journal
• Charlotte-Mecklenburg Historic Landmarks Commission
• Ask the Builder