
A triple-decker at 16 Church St. in Dorchester (left) blends in with the surrounding neighborhood building stock. Photo by Steve Adams | Banker & Tradesman Staff
Triple-decker construction may have a place in spurring housing production, but recent experiments in Boston and Somerville indicate only market-rate projects are financially feasible.
Somerville has seen an uptick in building permits for three-family dwellings in the past year after eliminating an income-restricted requirement. The city now allows three-family construction in the vast majority of its residential areas.
“It allows a historical structure to be built and allows it to continue to exist,” said Ward 1 City Councilor Matt McLaughlin, who represents East Somerville. “This is something pretty small for Somerville, but if every city and town in the state did this, it would go a long way to addressing the housing crisis.”
In late 2023, Somerville updated zoning to allow three-family structures including triple-deckers to be built as-of right in its Neighborhood Residential 2 zoning district, which includes side streets. It also removed a requirement that one of the three units in such projects be income-restricted.
Since then, the city has received 12 applications for new construction of detached or semi-detached three-family dwellings, according to data provided by the Somerville Inspectional Services Department. Another 11 applications were submitted for conversions from two- to three-family dwellings.
The elimination of the special permit requirement for three-family buildings has provided more certainty to developers to pursue projects, McLaughlin said.
‘Future Deckers’ Challenges Designers
Popularized during the late 19th century in Eastern and Central Massachusetts, triple-deckers’ construction declined sharply following the passage of the Massachusetts Tenement House law in 1912. Many jurisdictions also enacted zoning outlawing the building style amid an anti-immigrant backlash in subsequent years.
Seeing an opportunity for triple-deckers to fill hundreds of surplus building lots scattered throughout the city, the Boston Mayor’s Office of Housing last year sought innovative proposals for “Future Deckers” and offered a pair of parcels in Dorchester and Roxbury as proving grounds.
Despite the potential to acquire parcels at 379 Geneva Ave. and 569 River St. for a nominal price, none of the six proposals were able to make the finances work.
“Construction costs are a big challenge,” said Wandy Pascoal, manager of housing innovation and awards for the Boston Society of Architecture, which partnered with the city on the design competition. “And as we’ve seen over the last couple of years, the price points have been difficult for folks to grapple with.”
The request for proposals listed acquisition prices as low as $100 per parcel. But to qualify for additional city subsidies, developers were required to offer units at prices affordable to households earning a maximum of 120 percent of area median income. And at least half of units would be reserved for households earning a maximum 80 percent of AMI, with a maximum sales price of $297,200 per three-bedroom home.
Developers submitted a range of 21st century variations on the triple-decker.

Responding to a design competition on small-scale affordable housing prototypes, Athena Real Estate Development’s “Triple-Quadra-Decker” prototype included 12 condominiums built using modular construction techniques. Image courtesy of Hacin, Kaplan Construction and Athena Real Estate Development
Boston-based Athena Real Estate Development, in partnership with Kaplan Construction and architects Hacin, proposed a “Triple Quadra-Decker” including 12 units on the 569 River St. site.
The project incorporated modular construction techniques to reduce costs and construction timelines, but still fell approximately $300,000 per unit short of feasibility, Athena Real Estate Development President Lisa Serafin said. Construction costs were estimated at $600,000 per unit, approximately twice the maximum purchase price allowed under the competition’s guidelines.
“When the city is providing their land at no cost, they have expectations [for affordability],” Serafin said. “Part of it is where we are in the construction market and labor costs. A lot of projects are not working, even in the best locations.”
The results of the competition point to the need for additional subsidies if projects include an affordable component, Serafin said.
One such program was announced in June, when the city of Boston and MassHousing’s CommonWealth Builder program awarded a combined $20.7 million to three developers that are constructing 55 affordable condominiums on vacant city-owned parcels. The projects will be built by DVM Housing Partners in Mattapan, DREAM Development in Roxbury and Urbanica in Dorchester.
Growth Opportunity for Market-Rate Developers
Some developers finding sites on the private market have had success reviving the next generation of market-rate triple-deckers, and could find expanded opportunities as Boston rezones residential neighborhoods.
In Boston, three-family dwellings currently are allowed in neighborhood zoning subdistricts in Allston-Brighton, Jamaica Plain, Roslindale, Roxbury and West Roxbury. Three-family zoning as-of-right was added in portions of East Boston and Mattapan in 2024.

Steve Adams
After working at Boston-based developer Haycon Inc. in construction, Sean George founded his own firm to pursue infill housing developments. Scouring assessors’ data, he looks for vacant parcels of at least 2,000 square feet and tracks down owners to make offers.
A typical project was completed last May in Dorchester, where George and business partner Darren Maguire completed a triple-decker at 16 Church St. The developers acquired the property for $295,000 and received just over $1 million in construction financing from Needham Bank in May 2023.
The completed product blends classic triple-decker features such as bay windows and front porches with modern touches such as open floor plans and pendant lighting, with rents listed at $4,200.
Built with traditional techniques including central gas heating systems, such projects can be completed in under a year, George said.
George said the biggest hurdle to projects is time spent acquiring all of the necessary approvals, ranging from variances to fire and plumbing permits, which has taken as long as 260 days.
“Honestly, the city just has to fix the permit process,” he said. “Builders will build, and they’ll do it as quickly as they can to make it work.”