International Building Code (IBC)
Building codes are regulations that set out the standards to which buildings and other structures must conform. The International Building Code (IBC) is one of the codes established in the US by the International Code Council (ICC) and is applied by most of the country’s jurisdictions as well as internationally, although it can be amended to reflect local conditions and legislation.
IBC can be applied to most types of new buildings and is intended to ensure efficient and flexible building designs that protect health and safety and encourage the use of technological advances.
It requires that buildings and structures are classified under two categories:
- Use and occupancy.
- Type of construction.
Under use and occupancy there are several groups and subgroups that define a building’s specific use and are numbered based on the perceived risk the building poses to its occupants (the lower the number, the higher the risk). They are defined as follows:
| OCCUPANCY GROUP | SUBGROUPS | USES |
| Assembly |
A-1 (theatres, halls for performing arts) A-2 (restaurants) A-3 (worship and other recreation) A-4 (indoor arena) A-5 (stadiums) |
Places used for people gathering. |
| Business | B | Places used for providing services (e.g. banks, government buildings, police stations, offices). |
| Educational | E | Schools and day care centres. |
| Factory | F1 and F2 | Places used for manufacturing, packaging, repairing, etc. |
| High Hazard | H-1, H-2, H-3, H-4, and H-5 | Places involving hazardous materials (production, storage, etc.). |
| Institutional | I-1, I-2, I-3, and I-4 | Places where people are unable to leave without assistance (e.g. hospitals, care homes, prisons), |
| Mercantile | M | Commercial (e.g. shops, department stores, etc.). |
| Residential | R-1, R-2, R-3, and R-4 | Places providing overnight accommodation (e.g. houses, hotels, apartments, hostels, etc.). |
| Storage | S-1 and S-2 | Places where things are stored (e.g. warehouses, car parks, garages, etc.). |
| Utility and miscellaneous | U | Accessory structures and others (e.g. towers, barns, cooling towers, stables, tanks, retaining walls, etc.). |
Buildings can also be classified as a mixed occupancy type if they are occupied by more than one group type, and the different parts must conform to the codes for those areas. For example, a shopping centre with an underground car park will need to conform to both Group M and Group S.
The type of construction identifies the type of materials utilised for constructing the building or structure and classifies the level of combustibility and fire resistance associated with its elements (including primary structural frame, exterior and interior load-bearing and non-load-bearing walls, floor and roof). These are categorised as follows:
- Types I and II: Building elements are made of noncombustible materials.
- Type III: Exterior walls are made of noncombustible materials, the interior elements are made of any permissible material.
- Type IV: Exterior walls are made of noncombustible materials, interior elements are made of, or incorporate, timber.
- Type V: Structural elements comprise any permissible materials (A: Fire-resistance rated construction. B: Non fire-resistance rated construction).
[edit] Related articles on Designing Buildings Wiki
- Building codes.
- Building inspector.
- Building official.
- Building regulations.
- Code of practice.
- Design review.
- Certificate of occupancy.
- International Code Council ICC.
- International Existing Building Code (IEBC).
- International Residential Code (IRC).
- International Zoning Code (IZC).
- Licensed contractors in the USA.
- Performance specification.
- Planning permission.
- Office of Construction Services.
- Structural engineering codes.
- The role of codes, standards and approvals in delivering fire safety.
- What approvals are needed before construction begins.
- Zoning in the United States.
Featured articles and news
Guidance notes to prepare for April ERA changes
From the Electrical Contractors' Association Employee Relations team.
Significant changes to be seen from the new ERA in 2026 and 2027, starting on 6 April 2026.
First aid in the modern workplace with St John Ambulance.
Ireland's National Residential Retrofit Plan
Staged initiatives introduced step by step.
Solar panels, pitched roofs and risk of fire spread
60% increase in solar panel fires prompts tests and installation warnings.
Modernising heat networks with Heat interface unit
Why HIUs hold the key to efficiency upgrades.
Reflecting on the work of the CIOB Academy
Looking back on 2025 and where it's going next.
Procurement in construction: Knowledge hub
Brief, overview, key articles and over 1000 more covering procurement.
Sir John Betjeman’s love of Victorian church architecture.
Exchange for Change for UK deposit return scheme
The UK Deposit Management Organisation established to deliver Deposit Return Scheme unveils trading name.
A guide to integrating heat pumps
As the Future Homes Standard approaches Future Homes Hub publishes hints and tips for Architects and Architectural Technologists.
BSR as a standalone body; statements, key roles, context
Statements from key figures in key and changing roles.
ECA launches Welsh Election Manifesto
ECA calls on political parties at 100 day milestone to the Senedd elections.
Resident engagement as the key to successful retrofits
Retrofit is about people, not just buildings, from early starts to beyond handover.
Plastic, recycling and its symbol
Student competition winning, M.C.Esher inspired Möbius strip design symbolising continuity within a finite entity.
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.