A separate structure means a structure that is free-standing, like a separate barn, garage, shop, or greenhouse.

To qualify, you must use the separate structure in your business, but it doesn't have to be your principal place of business or a place where you see patients, clients, or customers.

For example, an artist's or musician's studio in a separate structure would qualify, even if another studio is the principal place of business. The owner of a floral business could also qualify by using a detached greenhouse at home, even though her store is somewhere else.