(Illustration via Pixabay) field_54b3f951675b3

AT A TIME when vacancy rates in some of Boston’s downtown office buildings remain high and foot-traffic has been slow to return in office only districts, long-floated ideas of converting commercial space to residential units are once again being considered. This is a move that could have positive implications, not just for increased housing production, but for the environment and historic preservation as well.

During the summer, Boston Mayor Michelle Wu announced the city’s plan to launch a new “Downtown Office to Residential Conversion Pilot Program,” a public-private partnership effort to incentivize the conversion of underutilized office buildings to residential use in downtown this fall. The mayor previewed this concept in her State of the City address as part of a holistic plan for creating a more integrated and streamlined system that connects multiple city goals for transit, sustainability, housing, and community-building.

Though office-based foot traffic has returned to many sections of the city, the downtown neighborhood is lagging behind Back Bay and the Seaport; a more integrated mixed-use neighborhood could be key to changing that dynamic.  Many of the priorities embodied in the mayor’s proposal were incorporated in a study released last fall that took a comprehensive look at how to re-invigorate Boston’s core downtown commercial district in a post-COVID landscape. The new program would offer owners of downtown commercial office buildings reduced property tax rates in return for immediately converting their buildings to residential uses.

Additional housing is clearly a need worth prioritizing, and particularly now that many downtown employers are embracing hybrid work styles, it makes sense to focus on downtown neighborhoods that have not typically had the 24/7 community vitality that mixed-use environments generate. But does the benefit of new housing alone spark the creativity, focus, and financing necessary to tackle this type of undertaking in an environment where only 12 percent of Boston’s office buildings (typically older Class B and Class C sites) are easy subjects for transformation?

Maybe. But the calculus becomes significantly more appealing when you consider environmental, historic preservation, and community-building benefits as well. Historic preservationists and environmental advocates are aligned on the benefits of preserving and reusing historic structures. Reuse rather than replacement simultaneously creates a continuity of historic fabric and addresses the negative environmental impacts of new construction.

A perfect example can be found in Emerson College’s Little Building. Constructed in 1917 across the street from the Boylston Street T station, this steel-framed structure originally housed 600 offices and multiple retail tenants – an early example of transit-oriented mixed-use development. After almost a century of use, the building was purchased by the college and converted to a residence hall. Over the next decades, signs of serious deterioration became evident, and Emerson needed to determine if the Little Building could meet future residential needs.

Though people talk a great deal about greenhouse gas and carbon dioxide emissions in the context of transportation, heating, and daily activities, we think less about these problems in terms of construction itself. Embodied carbon represents the carbon dioxide emissions associated with materials and construction processes throughout the entire lifecycle of a building or infrastructure, including the manufacturing of building materials, transport of those materials to the job site, construction practices used, and disposal of construction waste. Today’s new technologies and tools allow architects and builders to analyze the impacts of potential new construction in detail and measure how much new carbon creation is avoided by repurposing portions of the building’s structure and envelope.

The case of the Little Building makes it clear exactly how big the environmental benefits of reusing historic structures are. The team behind the Little Building project collaborated with Lambert Sustainability to conduct a study of the embodied carbon impacts of new construction versus renovation. A new building would have certainly benefited from today’s construction techniques, materials, and strategies to reduce carbon production. But even with those advantages, construction of both the new building envelope and structure itself would have created nearly 3,000 additional metric tons of CO₂ emissions. What does 3,000 metric tons of CO2 emissions really mean? It equates to the greenhouse gas emissions generated by an average passenger vehicle driven nearly 7.3 million miles – the equivalent of 2,425 one-way trips from Boston to Los Angeles. Conversely, it would take a fully-forested Boston Common nearly 100 years to sequester the same amount of carbon as embodied in the reclaimed portions of the Little Building.

Rather than demolishing the structure and constructing a new residence hall, Emerson decided to restore and renovate the Little Building with an increased bed count, structural upgrades, improved common areas, restored/recreated façade and historic ornamental features, and up-to-date safety and code elements. Clearly one of the biggest beneficiaries of Emerson’s decision to reuse the Little Building was the environment.

Boston’s mayor is known for her commitment to greenhouse gas reductions. Our governor has appointed the Commonwealth’s first cabinet-level climate chief. Instead of tearing down and replacing old buildings, preserving and repurposing them to meet the goals of increased housing production, vibrant communities, and environmental sustainability is without doubt a winning strategy.

Ross Cameron is a vice president at Elkus Manfredi Architects.