Ancillary area
An ancillary area of a building is an area that supports the function/s of the primary areas, that is, it is not part of the primary purpose of the building, but is required in order that the primary purpose can function.
Examples of ancillary areas include:
- Plant rooms.
- Cleaners’ rooms.
- ICT rooms.
- Building services rooms.
- Storage rooms.
- Circulation spaces.
In shared buildings, an ancillary area might support more than one occupant, e.g. a shared kitchen, meeting spaces, utility areas, and so on.
In residential buildings, ancillary areas include spaces which do not form part of the main dwelling directly, but nonetheless add some useful value, e.g. patio area, office, garage, conservatory, porch, utility room, and so on.
NB Planning Gateway One – Glossary, published on the Planning Portal, defines ancillary accommodation as: ‘Rooms or spaces in a building used to support the residential use, such as refuse stores, cycle stores, plant rooms and storerooms.’
[edit] Related articles on Designing Buildings
Featured articles and news
Commissioning Responsibilities Framework BG 88/2025
BSRIA guidance on establishing clear roles and responsibilities for commissioning tasks.
An architectural movement to love or hate.
Don’t take British stone for granted
It won’t survive on supplying the heritage sector alone.
The remarkable story of a Highland architect.
The Constructing Excellence Value Toolkit
Driving value-based decision making in construction.
Meet CIOB event in Northern Ireland
Inspiring the next generation of construction talent.
Reasons for using MVHR systems
6 reasons for a whole-house approach to ventilation.
Supplementary Planning Documents, a reminder
As used by the City of London to introduce a Retrofit first policy.
The what, how, why and when of deposit return schemes
Circular economy steps for plastic bottles and cans in England and Northern Ireland draws.
Join forces and share Building Safety knowledge in 2025
Why and how to contribute to the Building Safety Wiki.
Reporting on Payment Practices and Performance Regs
Approved amendment coming into effect 1 March 2025.
A new CIOB TIS on discharging CDM 2015 duties
Practical steps that can be undertaken in the Management of Contractors to discharge the relevant CDM 2015 duties.
Planning for homes by transport hubs
Next steps for infrastructure following the updated NPPF.
Access, history and Ty unnos.
The world’s first publicly funded civic park.
Exploring permitted development rights for change of use
Discussing lesser known classes M, N, P, PA and L.
CIOB Art of Building photo contest 2024 winners
Fresco School by Roman Robroek and Once Upon a Pass by Liam Man.