Window sill

The term sill (or cill), refers to the lowest horizontal element of a structure or body. In the construction industry this most commonly relates to a window sill, or sometimes to the threshold of a door.

A window sill (or windowsill, sometimes referred to as a window ledge) may be formed by timber, stone, slate, brick and so on, and is located at the base of the window. It may provide structural support for the window, and on the exterior may be inclined and project beyond the surface of the wall to shed rainwater.

In the interior, window sills are commonly formed by timber, and provide a ‘shelf’ at the bottom of the window.

[edit] Related articles on Designing Buildings

• Fenestration.
• Glass.
• Glazing.
• Lintel.
• Mullion.
• Rooflight.
• Sash windows.
• Stool.
• Transom.
• Types of window.
• Velux window.
• Window energy rating.
• Window frame.
• Window screens.
• Window.