The meaning of bay in the construction industry
The term ‘bay’ has numerous applications in the construction industry.
- When used in relation to a window, (as in ‘bay window’), it describes a part of the construction (in plan and elevation) that protrudes outwards from the main building line and is partly or wholly glazed. Bay windows take various shapes such as curved, rectilinear, polygonal etc.
- An elevation can also be divided into bays, whether these are subtle, eg delineated by rainwater pipes or movement joints, or created by more three-dimensional features such as a crenulated configuration of the walls.
- A bay in a building can also describe an internal area that is demarcated by structural elements. For example, in a building that comprises a grid with columns spaced at 6m-centres in both x- and y-directions, the result on-plan will be the creation of bays measuring 6m x 6m – assuming measurements are taken to the grid centre-lines.
- Bay can also refer to an area that is connected to and forms a small annexe to a larger area, such as a subsidiary area used for some function connected to the activity of the main area, e.g a loading bay.
- Bay (or bays) can also refer to single parking spaces that are created by painted lines on the ground.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this...
National Apprenticeship Week 2026, 9-15 Feb
Shining a light on the positive impacts for businesses, their apprentices and the wider economy alike.
Applications and benefits of acoustic flooring
From commercial to retail.
From solid to sprung and ribbed to raised.
Strengthening industry collaboration in Hong Kong
Hong Kong Institute of Construction and The Chartered Institute of Building sign Memorandum of Understanding.
A detailed description from the experts at Cornish Lime.
IHBC planning for growth with corporate plan development
Grow with the Institute by volunteering and CP25 consultation.
Connecting ambition and action for designers and specifiers.
Electrical skills gap deepens as apprenticeship starts fall despite surging demand says ECA.
Built environment bodies deepen joint action on EDI
B.E.Inclusive initiative agree next phase of joint equity, diversity and inclusion (EDI) action plan.
Recognising culture as key to sustainable economic growth
Creative UK Provocation paper: Culture as Growth Infrastructure.
Futurebuild and UK Construction Week London Unite
Creating the UK’s Built Environment Super Event and over 25 other key partnerships.
Welsh and Scottish 2026 elections
Manifestos for the built environment for upcoming same May day elections.
Advancing BIM education with a competency framework
“We don’t need people who can just draw in 3D. We need people who can think in data.”




















