Last edited 02 Nov 2020

Bay window

A bay window is a multi-panel window that projects outward beyond the external wall of a building. This outward projection forms a bay or interior recess and is supported by a sill height wall. Bay windows are typically rectangular or polygonal, and the most common internal angles are 90°, 135° and 150°.

Bay windows are a prominent feature of Victorian domestic architecture but were originally incorporated into designs during the English Renaissance period as a means of making a room appear larger, providing better views and admitting more natural light than a window which was flush with the wall line.

The interior recess created by a bay window can be used for storage by enclosing the lower area, or as a window seat with the addition of cushions and other soft furnishings. Alternatively, it can be used as a space to display decorative items, plants, and so on.

However, a bay window can require more heating or cooling to maintain a comfortable internal temperature due to the increased surface area of glazing. Consideration must also be given to the structural stability of the building foundations, as they must be capable of supporting the protruding windows and roof above.

In modern architecture, bay windows underwent a revival to become a characteristic feature of the Chicago School. Today, bay windows can be found in all types of domestic architecture as well as in apartment buildings.

There are several variations, including:

Canted: A bay window with a flat front and angled sides.
Bow: A bay window which is curved or arc-shaped.
Oriel window: This is a bay window found on an upper floor, typically supported from below by a corbel or bracket. This type of window allows the floor space to be extended without the dimensions of the foundation needing to be changed.
Mashrabiya: Highly decorative enclosed balconies that are characteristic of Arab architecture.