To comfortably fit a mezzanine, a building should have a minimum clear height of 18 to 20 feet. This provides roughly 8 to 9 feet of space both below and above the mezzanine deck, accounting for the thickness of the floor joists. If the mezzanine is intended for heavy equipment or high-clearance office space, a total building height of 24 feet or more is recommended to ensure a spacious environment.