600 Massachusetts Avenue

The 10-story transparent office building adds 400,000 sqft of multi-tenant space to the heart of Washington, D.C.’s bustling urban fabric. 600 Mass Ave provides a sustainable work environment for employees, utilizing a number of conservation and energy efficient design strategies to achieve LEED Platinum Certification. In the building skin, high-performance windows permit daylight to penetrate into the office space while rejecting 70% of solar heat gain. These measures, along with energy efficient building systems, are part of a whole building performance approach that was applied to the design of the building facade.

Enclos provided design-assist, fabrication and build services for the building enclosure, including curtainwall, punched windows, atrium walls, canopies and sunshades. With heavy involvement during early design stages, Enclos introduced a twin-span design strategy – curtainwall units that span two floors instead of one – instead of the more traditional single-story unitized module. Early input from the facade contractor during the design stage was instrumental in allowing the Enclos curtainwall installation teams to optimize their on-site efficiency.



Facade Area:

103,000 sq ft


Washington, DC




150 ft


Gould Property Company, Oxford Properties

General Contractor:

Clark Construction Group




SK&A Structural Engineers, PLLC


WBC Craftsmanship Award
Washington Building Congress, 2018

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