A mezzanine is, strictly speaking, an intermediate floor in a building which is partly open to the double-height ceilinged floor below, or which does not extend over the whole floor space of the building. However, the term is often used loosely for the floor above the ground floor, especially where a very high original ground floor has been split horizontally into two floors.

Mezzanines may serve a wide variety of functions. Industrial mezzanines, such as those used in warehouses, may be temporary or semi-permanent structures.

Industrial mezzanines

In industrial settings, mezzanines may be installed (rather than built as part of the structure) in high-ceilinged spaces such as warehouses. These semi-permanent structures are usually free-standing, can be dismantled and relocated, and are sold commercially. Industrial mezzanine structures can be supported by structural steel columns and elements, or by racks or shelves. Depending on the span and the run of the mezzanine, different materials may be used for the mezzanine's deck. Some industrial mezzanines may also include enclosed, paneled office space on their upper levels