600 Massachusetts Avenue

Washington, DC

Close Up

  • Architect


  • Engineer

    SK&A Structural Engineers, PLLC

  • GC

    Clark Construction Group

  • Completion


  • Building Type


  • LEED Rating

    Platinum certified

  • Program

    10 stories (150ft), 400,000 sqft

  • Fa├žade Area

    103,000 sqft of custom enclosures, including: 62,000 sqft of curtainwall; 14,700 sqft of punched and strip windows; 7,500 sqft of entry wall; nearly 9,000 sqft of interior glazing; canopies, glass bridges, wing walls and sunshade features





  • WBC Craftsmanship Award, Washington Building Congress, 2018


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 façade.

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 façade contractor during the design stage was instrumental in allowing the Enclos curtainwall installation teams to optimize their on-site efficiency.