Mezzanine
An intermediate floor built within a warehouse unit's clear height, used for office, storage, or light assembly space without expanding the building's footprint.
Definition
A mezzanine is a partial second level built inside a unit, typically supported on steel columns and accessed by a stairway. It uses vertical space that would otherwise sit empty above racking or office areas. In small bay and flex buildings with 18 to 24 feet of clear height, a mezzanine adds office, storage, or light assembly area without expanding the building's slab footprint or triggering the cost of a full second story. Mezzanines are usually tenant-installed improvements rather than landlord-delivered, since the layout depends on how a specific tenant plans to use the space. Building codes typically cap mezzanine area at a percentage of the floor below, often 33%, before the space is reclassified as an additional story with different fire and egress requirements.
Example
A tenant leases a 4,000 SF unit with 22-foot clear height. They build a 1,200 SF steel mezzanine over the rear third of the warehouse for parts storage and a small office, staying under the 33% floor-area threshold that would require it to be treated as an additional story.