Constitution Square

A Revival Development in Northeast D.C.
Clark's unparalleled expertise and experience proved vital to carefully plan all of the simultaneous activities on-site and in dealing with unplanned events and challenges. Stonebridge made the right decision in hiring Clark to construct, what certainly proved to be, a uniquely challenging project.
Mark Allard, Project Manager, Stonebridge Associates, Inc.
Washington, D.C.
StonebridgeCarras, LLC
3,100,000 Square Feet
Year Completed: 
LEED Platinum - One, Two & Three Constitution Square
LEED-CI Silver - Two Constitution Square Interiors
LEED Silver - Residential Building Two
LEED Platinum - Three Constitution Square

The Constitution Square development complements the District of Columbia’s vision for the NoMa neighborhood as a pedestrian-friendly mix of office, residential, and retail space.

Constitution Square is a 2.6 million square-foot, mixed-use development that spans a full city block. It consists of three office buildings and two residential buildings. Two entrances to the New York Avenue-Florida Avenue-Gallaudet U. Metro station serve the complex. 

One Constitution Square

One Constitution Square is as 12-story, 450,00 square-foot, core-and-shell office building with four stories of below-grade parking. The exterior is a combination of architectural precast panels, curtain wall, and punched windows. 

The Constitution Square jobsite required complete beginning-to-end utility installation. At the outset of construction, the project team brought generators to the jobsite to provide power until temporary utility feeds were provided. Additionally, Clark performed pre-excavation work to locate any unidentified utilities during excavation and was able to modify the support of the excavation system accordingly to keep the in-service conduit in the original location. This work was done with no impact to the construction schedule.


Working with the client, the project team ensure to maximize LEED credits, earning LEED Platinum certification. Clark utilized a grey-water tank reclamation system.

Two Constitution Square

Two Constitution Square is a 12-story, 635,000 square-foot, core-and-shell office building with three stories of below-grade parking. The building is a cast-in-place concrete structure and features a three-story sunlit atrium with a glass ceiling with point supported glazing. The building's exterior combines curtain wall and architectural precast concrete. In addition to office space, the facility includes a first floor health center, various workstations, and multiple conference and training rooms. 

The project features numerous Sensitive Compartmented Information Facility (SCIF) rooms and a 12th floor expansion to accommodate the main tenant: the U.S. Department of Justice (DOJ). Clark also provided general contracting services to DOJ for the fit out. The completed space earned LEED Silver certification for Commercial Interiors.


The Two Constitution Square building earned LEED Platinum certification, exceeding the original goal of LEED Gold certification. The building includes an 18,300 square-foot green roof and a grey-water system that uses condensate from the building's cooling towers for the toilets. During construction, 75 percent of construction waste was recycled, and 20 percent of new building materials were made from recycled content.

Three Constitution Square

Three Constitution Square is a 12-story, 350,000 square-foot Class-A Office building. The project includes more than 100 below-grade parking spaces, as well as 12,000 square feet of retail space.

With a 30,000 square-foot floor plate, single column line, and a 30-foot x 35-foot grid, the building was design and constructed with the flexibility to accommodate demanding tenant layouts. The building features a 40-foot water wall in the lobby and abundant green space in the 8,000 square-foot private courtyard on the first floor.

The facade is comprise of a precast system, with punched windows, curtain wall, and metal panels. The completed structure consists of 326,120 pounds of post tension cables, 1,394 tons of reinforcing steel, and 25,000 cubic yards of cast in place concrete.

To prepare for the building's three-story underground parking garage, Clark Foundations' crew installed a combination secant pile wall and drilled soldier beam-lagging wall. Adding to the scope's complexity was the proximity of the NoMa/Gallaudet University Metro Station which, in some spots, was located less than five feet from the sheeting system. The foundation system was supported by two tiers of internal bracing (continuous water, corner braces, and raker braces).

In addition, the team relocated two active storm drains behind the sheeting line and supported them during excavation. The crew also had to work around running gravel fill and groundwater during construction. Despite the project's complexity and potential complications, the system moved less than 1/16" during the construction process and the Metro station was never impacted.

Three Constitution Square earned LEED Platinum certification.

Flats 130 at Constitution Square and Hilton Garden Inn

The Flats 130 at Constitution Square and Hilton Garden Inn jointly occupy a 13-story, 671,000 square-foot residential building with retail. Clark constructed 440 apartment units, core-and-shell space for the 204-room hotel, a 50,000 square-foot Harris Teeter grocery store, and 30,000 square feet of retail space. The building’s skin is primarily brick with cast stone accents and punched glass windows. The cast-in-place concrete structure also includes three levels of below-grade parking.

The luxury apartment tower offers amenities such as a fitness center, club and game rooms, a WiFi lounge, and a rooftop pool and sun deck. The units range from studio to two-bedrooms with a den, and offer a wide array of finishes. There are courtyards on the second floor of the east and west wings of the building, and green roofs on the 13th floor and east 7th floor. The building also connects residents with the outdoors through a system of courtyards and terraces with outdoor fireplaces, water features, a pet park, and grills.

Constitution Square Residential Building Two

Part of the Phase 2 development currently under construction, Clark provided preconstruction and general contracting services for the construction of Constitution Square Residential Building Two, a 13-story, 203-unit apartment building. Units range from studios to two bedrooms with a den, and are served by a slew of amenities, including fitness center, community rooms, pools, and a one-half acre dog park. In addition, there are 106 parking spaces provided in three levels of below-grade parking and approximately 3,000 square feet of street-level retail.

Residential Building Two earned LEED Silver certification.

Mid-Atlantic Construction Magazine - Green Building Award of Merit
Mid-Atlantic Construction Magazine - Green Building Project of the Year
NAIOP Maryland/DC - Awards of Excellence, Best Sustainable Design - New Building
NAIOP MD/DC Award of Excellence - Best Urban Office150,000+ Square Feet
USGBC - National Capitol Region Project of the Year, Neighborhood Development
Washington Business Journal - New Office Development of the Year
Washington Business Journal - Best Community Impact Runner-Up
WBC Craftsmanship Award - Doors & Windows/Curtain Wall
WBC Craftsmanship Award - Interior Stone & Marble