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Triple-deckers were once an affordable solution to Boston’s housing crunch — and can be again

Once a beacon of affordable housing, our city’s triple-deckers now serve as a reminder of how architecture can rise to meet the challenges of the moment.

Boston's iconic triple-deckers, some seen here around the 600 block of Morton Street, Mattapan.David L. Ryan/Globe Staff

At the turn of the 20th century, working-class Boston residents faced a lack of affordable housing and, as a result, the diverse working class struggled to live close to where they worked and faced low rates of homeownership. One of Boston’s most iconic architectural styles, the triple-decker, was a solution to these challenges, not unlike many of the challenges Boston faces today.

Between 1880 and 1930, Boston responded to the needs of the working class by constructing an estimated 15,000 triple-deckers. This type of housing was popular with immigrants and Black Bostonians as Boston experienced different migration patterns. It also offered an affordable path to homeownership, since a family could live in one unit and rent out the other two, often to relatives. Triple-deckers became a popular and economically viable example of multigenerational housing throughout the region.


But triple-deckers, with their diverse working-class residents, soon became a lightning rod for racist and anti-immigrant sentiment that fueled policy and building code changes.

A triple-decker in Mattapan.David L. Ryan/Globe Staff

New zoning prevented the building of triple-deckers in Boston. Between 1910 and 1930, as anti-immigrant policies were enacted throughout the country, other New England municipalities passed laws and zoning that further limited the building of triple-deckers and other multifamily housing.

Over the years, many triple-deckers throughout New England have been demolished and replaced with single-family houses. In Boston, efforts to preserve triple-deckers have been successful in many cases, although some triple-deckers have been converted into condominiums that are sold as three individual units and are often prohibitively expensive for working-class Bostonians. New triple-deckers are difficult to build today due to zoning restrictions and requirements such as parking minimums, zoning restrictions for building on small lot sizes, and onerous permitting policies that often price out the working class.

Once a beacon of affordable housing, the city’s triple-deckers now serve as a reminder of how architecture can rise to meet the urgent need for housing solutions along a spectrum of affordability.


Architecture can be a powerful tool for justice. Community prejudice and restrictive building codes are among the factors that led to the end of affordable triple-deckers. A multi-pronged approach, including design, zoning, permitting, community engagement, innovative construction methods, and new financing models will help the city meet the challenges that threaten the future of middle-scale housing.

A triple-decker renovation-in-progress in Dorchester. The finished project was featured on “This Old House” in May.Kevin O'Connor

Participatory zoning law reform that includes neighborhood stakeholders in the process could create necessary changes to outdated zoning. As it stands, developers must participate in a lengthy, costly, and piecemeal process to have antiquated zoning laws relaxed for a particular parcel. This issue slows the development of middle-scale housing and disproportionately affects marginalized communities who have had infill lots lay vacant for decades. In many cases, these empty lots formerly housed triple-deckers.

Infill development can increase the overall production of affordable and workforce housing. Participatory zoning reform and greater resident engagement can better promote infill development. The Boston Society for Architecture and the City of Boston iLab’s current Request for Ideas aims to do just that, by generating innovative ideas for affordable, middle-scale housing that can be built on small sites throughout Boston.

Boston should also encourage alternate construction methods through tax incentives to create reliable demand for local prefabricated components. Artificial intelligence technology can also be used to optimize site plans and gain efficiencies in construction. The building community should embrace new construction techniques and technologies to combat the rising cost of housing. Workforce development training could further the advancement of these new approaches.


Much like Boston at the turn of the 20th century, present-day Boston is in dire need of housing solutions. Luckily, the city has the tools and know-how to empower change through architecture to create more affordable middle-scale housing to combat rising home prices, high rent costs, and low rates of homeownership. And that solution doesn’t benefit only the Bostonians who inhabit these homes; it also creates a ripple effect throughout other communities, which improves local economies and creates opportunities for families to thrive.

The question isn’t whether we as a city can work toward this reality, but rather whether we want to prioritize it.

Greg Minott is president of the Boston Society for Architecture and cofounder and managing principal of DREAM Collaborative.