A window sash (or casement) is the movable part of a window or door that swings, slides or tilts within the frame. The sash is the component you actually open and close. For windows it is also called a window sash; for doors, a door leaf.
Function of the sash
- Opening and closing — the sash provides access to ventilation or passage
- Sealing — when closed, the sash seals the opening against wind and water
- Glazing — in windows, the sash carries the glass (single, double or triple glazed)
- Security — locks and hardware are mounted on the sash
Types of sashes
| Type | Description | Application |
|---|---|---|
| **Side-hung casement** | Swings on a vertical axis (hinges at the side) | Standard windows and doors |
| **Bottom-hung (tilt)** | Tilts on a horizontal axis at the bottom | Fanlights, ventilation |
| **Tilt-and-turn** | Can both tilt and swing | Modern windows, bedrooms |
| **Sliding sash** | Slides horizontally or vertically | Sliding doors, sash windows |
| **Top-hung** | Tilts outward from a top hinge | Awning windows |
Sash vs. frame
| Sash | Frame | |
|---|---|---|
| **Movable** | Yes | No (fixed in the wall) |
| **Carries glass/panel** | Yes | No (carries the sash) |
| **Components** | Glazing bead, glass, seal, hardware | Stiles, rails, sill |
Parts of a window sash
- Stiles — the vertical timber or aluminium members of the sash
- Rails — the horizontal members (top rail and bottom rail)
- Glazing bead — holds the glass in place within the sash
- Weatherseal — fitted all around for wind and watertightness
- Hardware — hinges, handle, stay, locking points
Adjusting a sash
A sticking or poorly closing sash can often be adjusted yourself:
- Check that the hinges are tight (tighten the screws)
- Adjust the hinge with an Allen key (height, depth, lateral position)
- Check the locking points and adjust them if the sash does not close properly
- Lubricate hinges and locking points with silicone spray
Related terms
- Frame
- Awning window
- Tilt-and-turn hardware
- Glazing
- Rebate size
- French door