enclosed shaft

covered shaft

An interior enclosed space that extends through one or more stories of a building, connecting openings in successive floors, or the floors and roof; must be covered at the top.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Their 10,000-sq-ft operation in the marine manufacturing mecca of Southern Florida produces watertight, enclosed shaft systems that run through low-friction thrust bearings.
A residential elevator requires an enclosed shaft, as does a commercial elevator, albeit with a smaller mechanical room and overrun space at the top of the unit.