Bay (architecture)

Lyme Park in Cheshire, England. The main facade is divided by pilasters into fifteen bays.

Looking down the center aisle of the Saint Roch Parish Church of Lemery, Batangas, Philippines, the spaces between each set of columns and roof trusses are a bay

An interior bay, between the supports of the vaults, in Lyon Cathedral, France.

In architecture, a bay is the space between architectural elements, or a recess or compartment. The term bay comes from Old French baee, meaning an opening or hole.

Examples

1. The spaces between posts, columns, or buttresses in the length of a building, the division in the widths being called aisles. This meaning also applies to overhead vaults (between ribs), in a building using a vaulted structural system. For example, the Gothic architecture period's Chartres Cathedral has a nave (main interior space) that is "seven bays long." Similarly in timber framing a bay is the space between posts in the transverse direction of the building and aisles run longitudinally.
2. The openings for windows in a wall. For example, in Georgian style, at Mulberry Fields in Maryland, the building is described as a "5 bay by 2 bay facade," meaning a "5 windows by 2 windows" exterior.
3. A recess in a wall, such as a bay window.
4. A division of space such as an animal stall, sick bay, or bay platform.
5. The space between joists or rafters, a joist bay or rafter bay.

East Asia

The Japanese ken and Korean kan are both bays themselves and measurements based upon their number and standard placement. Under the Joseon, Koreans were allocated a set number of bays in their residential architecture based upon their class.

See also

• Architectural elements