In general, assuming that the existing location of your business has not reached maximum lot coverage, on-site expansion is the easiest way to add additional customer and inventory capacity.
Each retail and commercial space has a defined occupational capacity, which limits the number of persons that can be in a room or total combined space at the same time. This capacity is set by both building and fire code, and determines the safe occupational capacity for your businesses operations. These conditions are set during design and enabled at the issuance of a Certificate of Occupancy (CO) for your business location.
Parking, interior space, and life safety considerations
Interior volume and accessibility (life safety) variables determine how many total persons can safely occupy your business at one time, and based upon the total number of persons able to be served, your business location is assigned the minimum number of standard and accessible parking facilities required. In some circumstances depending on the zoning district you are in, or the number of available off-street parking facilities adjacent to your location you may not be required to provide additional on-site parking.
Similarly, spaces designated for public customer occupation and on-site inventory and material storage are defined differently from one another by building and fire code. Business owners will need to consult with building safety and fire personnel to determine whether ideas for reconfiguration of interior space will be practical under current codes.
Constructing on-site attached or detached structures
Additional on-site attached or detached structures may impact the number of additional parking spaces required, and would be limited by the number of parking spaces (if applicable) able to be added or reconfigured by the structure displacing existing parking spaces. Some zoning districts have limitations on on-site detached accessory structures, or the permissible use of those structures in addition to the primary structure's use.
See the Business Portal section on Location & Zoning to determine other requirements on your on-site expansion.