Mezzanines have been in use for many years by being built conventionally during the construction phase of a building itself. In residential construction, the second floor of a house could be termed a mezzanine. 

In commercial applications, builders attach bar-joists to existing building columns or they place columns for a mezzanine in particular locations and then attach bar-joists that then hold metal decking called 'B' decking. (See different types of decks) The owner of the building might not have chosen to have installed a second floor at the time of building construction for several reasons; cost involved in the structure, no immediate need or they had land available to expand in the future. As you have perhaps noticed in life, things change and the need for additional room becomes a necessity. At this point in a corporations life, one of two things must now take place: (1) Add onto the building now in or (2) move to a larger building. If choice (1) is selected, this would require the acquisition of land, locate suitable contractors and start a process that is costly and messy. Choice (2) is not much better as the disruption to the operation can be a real headache and logistics of moving can present challenges.

As the material handling industry assisted corporations with the movement and storage of their product, several material handling salespersons recognized that they could assist their customers with their storage problems by using pallet rack and slotted angle with bar-grating (see flooring options) that had been used in industrial applications for years as a walk type grating. Some individuals even fabricated their own second floor structures by having engineers design and fabrication shops build these 'mezzanines'. At some point in this process several individuals decided that they could make these 'mezzanines' more efficient and better than individuals could. Then along came the mezzanine manufacturers that now could use that unused air space. A second floor could be manufactured off site, while the area could be prepared. This structure then would be shipped to the customer, off loaded, assembled like a big erector set and they would now have a second floor inside of their building. Thus the mezzanine industry was born.