Quick answer
Every building space is classified by how it is used, such as business, mercantile, assembly or storage. If your business falls in a different occupancy group than the previous tenant, or the same group with higher risk, it is a change of use. That usually needs a permit with drawings and a new certificate of occupancy, and it can trigger upgrades to exits, restrooms, fire protection, ventilation and structure.
A change of use is the most common surprise in commercial leasing. The space looks ready, but the code sees a gym where a shoe store was, and the requirements change with it.
Occupancy groups in plain English
- Business (B): offices, banks, clinics, salons
- Mercantile (M): retail stores
- Assembly (A): restaurants and bars above a certain occupant load, gyms, churches, event spaces
- Educational (E): schools and many daycares
- Factory (F) and Storage (S): manufacturing, warehouses
- Residential (R) and Institutional (I): housing, care facilities
Changes that usually trigger upgrades
- Retail or office to restaurant, bar, gym, church or event space (more people per square foot)
- Office to daycare or school
- Warehouse to occupied space, or adding living units to commercial buildings
What the city may require
- More or wider exits, panic hardware and emergency lighting
- More restroom fixtures for the new occupant load, and accessibility upgrades
- Sprinklers or fire alarms when the new use crosses a size or occupant threshold
- Ventilation for the new number of occupants
- Structural review if floor loads increase, for example storage, gym equipment or crowds
- Zoning approval if the use is not allowed by right
Check before you sign the lease
Ask for the space’s current certificate of occupancy and the previous use. A short code review by an engineer before signing tells you whether you face a simple TI or a costly change of occupancy, which is a strong negotiating point with the landlord.
What to send us
- Address, suite and the current or previous use
- Your planned use, seat count or occupant estimate
- Floor plan or photos of the space
- The existing certificate of occupancy, if available
Get a fixed-fee quote. See also tenant improvement permits.
Common questions
Do I need a new certificate of occupancy for a new business?
If the use changes, usually yes. Many cities also require a new certificate whenever a new business opens, even in the same use.
Is a restaurant an assembly occupancy?
Restaurants and bars with an occupant load above the code threshold, commonly 50 people, are assembly occupancies. Smaller ones are often treated as business occupancies.
Does a change of use always need sprinklers?
No. It depends on the new use, size and occupant load. A code review answers this before you commit.
Who decides the occupancy group?
The building official, based on how the space is actually used. Your design professional proposes it in the drawings.