FOX Architects based in McLean, Va., used glass extensively as part of the recently completed building at 1129 20th St. in Washington, D.C., helping create sustainable architecture.”It’s been said the greenest building may be the one that’s already built,” says J.P. Spickler, AIA, principal-in-charge of the project. “This project is about the reuse and transformation of the building into a new, sustainable, state-of-the-art office building. Rather than tear the building down, we gave it new life.”

The original eight-story structure was built in 1968 and had no significant upgrades since its construction. It originally contained 136,000 gross square feet and two levels of underground parking. FOX Architects increased the building in height by two floors, adding 45,000 square feet. A new façade and new building systems were woven through the existing structure.

According to Spickler, the building’s new façade is a unitized glass and metal curtainwall system.

“Its design is intended to express, in an honest manner, the building’s structure and function. It is intended to be a sophisticated glass wall that allows views out and natural light in,” he explains.

Horizontally fritted glass at the lower margin of the office floors provides some privacy at the credenza level. Carefully studied mullion hierarchy identifies floor lines and creates movement as light and people experience the façade from different oblique angles. Spickler adds that the glass corners reinforce the fact that the building is a freestanding structure.

A central reveal in the building’s curtainwall provides a break to the overall façade system and aligns with the building’s internal core and central lobby.

“The building opens here to permit a more direct visual and physical connection to the street. The two halves of the building float off the structural frame to convey lightness,” Spickler notes.

The glass within the central reveal is intended to create movement in the façade and expose the structure and functions behind. Additionally, the reveal creates an opportunity for two more corner offices, so each typical floor has four corner office opportunities, where previously there were none.

U.S. Green Building Council (USGBC) LEED-New Construction certification is pending currently. However, based on the points total as of construction completion, the building is expected to be Gold certified.

“Achieving a high Gold rating reinforces the importance of projects like this,” said Spickler. “There is great value in recycling and transforming our urban fabric, rather than systematically replacing it in total.”