Hickok Cole

The 80 M Street project is the first-ever mass timber renovation of a commercial office building in Washington, D.C. Located in the city’s Navy Yard district, the project adds 107,000 square feet in three floors of overbuild to the existing seven-story, 265,000-square-foot building. Given mass timber’s novelty in the city, the extension design underwent a thorough vetting process before it was approved by the D.C. code authority. The structural and fire engineers developed new concepts for custom concealed, two-hour-rated mass timber connections, a consideration not addressed prescriptively within the code. During the design-assist phase, the timber design-assist contractor further detailed and tested the connections to secure final approval. Close collaboration with local code officials helped establish an alternate compliance path to allow mass timber to be used within the current permitting process. The 80 M Street project demonstrates the potential for mass timber construction by taking full advantage of its core benefits. The building incorporates approximately 1,400 tons of mass timber—a 100 percent renewable material with the ability to sequester carbon dioxide emissions. The procurement and installation strategy served to minimize carbon emissions even further by making efficient use of shipping timelines and storage locations. 80 M’s mass timber structure took just eight weeks to install—compared with the 14 weeks it typically takes to build a similar structure using concrete or steel.