This occupied renovation in Washington, D.C.’s central business district incorporates a vertical expansion and connection of two office towers—2000 L Street and 2001 K Street—into a single 1-million-sq-ft lot. 

The team says that this is the largest and most complex occupied renovation project of its type in the city. Its scope of work included adding four floors of long-span, structural steel framing and a new mechanical system while maintaining and phasing the removal of existing penthouse equipment and installing a temporary mechanical system to keep the office building running. 

The result is a combined building with a 25,000-sq-ft main lobby with statuary marble walls, acoustic wood ceiling and other high-end finishes. Spanning two levels, the lobby has a 12-story glass atrium. The job included removing 2000 L Street’s existing 1960s precast and punch-window facade and replacing it with six unique curtain wall systems.

To carry out an occupied facade replacement, crews used temporary weather-resistant partitions that separated tenants from ongoing construction. 

Completed on schedule, the job was divided into quadrants, with workers replacing two quarters of the facade at any given time. The team also coordinated closely with the building’s management to move tenants back 5 ft from the exterior wall to create swing spaces. The team says constant communication was critical to this effort.

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