Sash Window Parts Explained: A Glossary with Diagram

A traditional box sash window has two sliding sashes held in a frame by beads, balanced by hidden weights on cords. Knowing what each part is called makes it much easier to describe a problem, understand a quote and compare installers. Use the labelled diagram and glossary below as a reference.

Labelled diagram of a box sash window

The frame

• Box frame: the hollow frame around the sashes that contains the weights. Also called the case, hence “sash and case” windows in Scotland.
• Head: the top of the frame.
• Pulley stile: the inner side of the frame that the sashes slide against, with the pulleys set into it.
• Pulley: a wheel near the top of each pulley stile that the cord runs over.
• Pocket: a removable panel in the pulley stile that gives access to the weights.
• Sill: the sloping bottom of the frame that sheds rainwater. Sills are the part most prone to rot.
• Linings: the boards that form the inner, outer and back faces of the box.

The beads

• Staff bead: the inner bead that holds the lower sash in place. It is removed to take the sash out.
• Parting bead: the thin bead between the two sashes that keeps them in separate tracks. Often replaced with a brush-seal version when draught-proofing.
• Outer lining (or blind stop): the outer edge that keeps the upper sash from falling outwards.

The sashes

• Sash: each sliding frame holding glass. The upper sash slides in the outer track, the lower sash in the inner track.
• Stiles: the vertical sides of each sash.
• Top rail and bottom rail: the horizontal top and bottom of each sash.
• Meeting rails: the rails where the two sashes meet in the middle; the catch or lock is fitted here.
• Glazing bars (astragals): the thin bars dividing the glass into panes, such as two-over-two or six-over-six. See our Georgian and Victorian window guides.
• Horns: short extensions of the upper sash stiles below the meeting rail, common on Victorian windows. They strengthen the joint for heavier glass.
• Putty or glazing beads: hold the glass into the sash.

The balancing system

• Sash cord: the cord connecting each sash to its weight. See how to repair a sash window cord.
• Weights: cast-iron or lead weights inside the box that balance each sash.
• Spiral balances: a modern spring alternative to weights. Compare them in sash window weights vs spiral balances.

Hardware and fittings

• Fitch fastener (sash catch): the catch on the meeting rails that pulls the sashes together.
• Sash lifts and pulls: handles on the bottom rail used to raise and lower the sash.
• Sash stops: small bolts that limit how far a sash opens.
• Restrictors: devices that limit the opening, usually for child safety.
• Sash locks: keyed or screw locks through the meeting rails. Read our sash window locks and restrictors guide.

Using the right words with an installer

Knowing the parts helps you describe problems clearly, for example “the lower sash won’t stay up because a cord has snapped” or “the sill and bottom rail are soft”. That gets you more accurate quotes. For typical prices, see our sash window repair costs price list, and for bigger jobs, our sash window restoration guide.

Find a sash window specialist near you.

Frequently asked questions

What are the parts of a sash window called?

The main parts are the box frame, sill, pulleys, weights and cords, the staff and parting beads, and the two sashes, each made of stiles, rails and glazing bars, meeting at the meeting rails.

What is the parting bead on a sash window?

The thin strip between the upper and lower sashes that keeps them in separate tracks. It is often replaced with a brush-sealed version during draught-proofing.

What are the horns on a sash window for?

Horns strengthen the joint at the bottom of the upper sash. They became common in the Victorian era when larger, heavier panes of glass were used.

Where are the weights in a sash window?

Inside the hollow box frame on each side of the window, reached through a removable pocket in the pulley stile.