A casement window is a style of window in which the window sashes are attached to the side of the frame with one or more hinges. Where a single-hung or double-hung window has sashes that slide vertically or horizontally, a casement window can have one sash or two sashes that operate independently of one another. A crank is used to open the window outward, or in some cases, upward. 

Many parts come together to create a casement window and understanding these casement window part names will help you better understand and service the window.

Casement Window Parts

Frame

The frame of a casement window is the exterior box that is recessed into the structure to provide support for the window sashes and the rest of the casement window parts.

Head

The head refers to the upper horizontal section of the frame that forms the top of the window.

Casing

When the frame is installed in the structure, there is a gap between the frame itself and the wall. The casing is the decorative molding that hides this gap and creates an aesthetically pleasing finish on the window.

Sill

The window sill is the part of the window that protrudes from the wall to create a ledge.

Window Sash

The window sash is the operable section of the window that contains the glazing and swings outward. In a casement window, the sash can also be referred to as a casement, thus the name.

Window Glazing

The window glazing is the glass that is secured in the window sash. In the early days of glazing, glass panels could only be manufactured in small panes, so grilles were added to hold all of the pieces of glazing together. 

Today’s windows typically feature one larger piece of glazing with decorative grilles that create the effect of a traditional window sash. In many cases, these grilles are sandwiched between two panes of glass to create a double-glazed window. Where three panes of glass are used, it is a triple-glazed window.

Grilles

Grilles are the strips of wood or other material that hold the glass in place in the sash. These are largely decorative, as today’s glazing is typically one piece.

Mullion

The mullion is the strip of wood or other material in the center of a casement window that helps to seal the window when it’s closed.

Crank Operator

The crank operator is attached to an arm that opens the window as the crank is turned.

Hardware

Hardware is a catch-all term to describe the crank operator and arm, hinges and locking mechanisms for casement windows.

Window Hinge

The window hinge attaches to the side of the window frame as well as the sash to allow the sash to swing open. In some cases, the hinges are located on the top of the window so the casement sash can swing up rather than out. This is also called an awning window.

Locking Handle

The locking handle is attached to the mullion in a double casement window and the frame in a single casement window. The keeper is attached to the window sash so it can be locked for safety and security.

Casement Window Wear and Tear

Windows really take a beating, especially from the exterior. They are exposed to the elements daily, and moisture, sun, snow, sleet and wind wear on the materials. Over time, wooden casement windows may warp or swell, causing difficulty opening or closing the window. The crank operator can also wear out over time.

Because the arm of the crank operator is only attached to the bottom part of the window, it continually exerts pressure on just the bottom of the casement sash as it’s opened and closed. The weight and pressure are unevenly distributed between the bottom and top parts of the sash. This can cause the sash to warp, sag or bow over time and create window sash issues.

Replacing Casement Window Parts with Fenster

Fortunately, you can replace casement window parts rather than replace the entire window. Sometimes, replacing the casement window hardware, like a faulty crank or weakened hinge, is all you need to do to get your casement window sash back in working order. In other cases, a new sash may be required to restore the window to its original condition.

Original wood casement window sashes can be difficult to find if the original manufacturer’s components have become obsolete or are proprietary. To remedy the situation, our experts at Fenster have engineered casement window sashes that are near replicas of many popular brands. Our attention to detail guarantees that our sashes will perform better than the original while maintaining design continuity with the frame and other windows.

Contact our team today to discuss replacement casement window parts for your project.