An annex is a section of a building or a neighboring building that is utilized in conjunction with the main building. An annex is a structure in the parking lot that serves as additional office space to support the main building's office space. A building got a new wing. That would be considered an annex. There are three types of annexes: ancillary, auxiliary, and incidental. Ancillary annexes are necessary for the proper use and enjoyment of the main building. These include things such as security offices, storage rooms, staff lounges, etc. Auxiliary annexes provide facilities for special purposes such as workshops, libraries, laboratories, classrooms, rehearsal spaces, etc. Incidental annexes are used for other purposes such as parking, trash disposal, and water supply lines and are not required for normal operation of the main building. In most cases, buildings have more ancillary space than auxiliary or incidental. This is because ancillary facilities are needed day-in and day-out while auxiliary and incidental facilities are used for only certain events or activities associated with the main building. The amount of ancillary space varies depending on the type of institution. For example, schools need more ancillary space due to the daily use of facilities such as labs, gymnasiums, and dining halls.