Making the most of a cherished home is not a new concept, but across the country, more and more states are making it easier for homeowners to do just that—by passing laws to allow property owners to build an Accessory Dwelling Unit (ADU) by right.
For one family in the Boston neighborhood of Dorchester, the state’s relatively new ADU law—passed in August 2024—coincided with their plans to convert the attic of their 1895 house into a living space for a family member.
Broadly defined as a small residential living space located on the same lot as another home, ADUs are becoming more common mainly because state and local policies are granting homeowners the right to build one without requiring excessive permits and approvals. In Massachusetts, the ADU law outlines standards such as having a separate entrance and not exceeding a certain square footage, but otherwise simplifies the endeavor.
ADUs can be inside an existing home (think: a basement or attic turned into an apartment), attached to a primary residence as an addition, or completely detached in a back or side yard. Most importantly, building an ADU presents an affordable option for housing—and one that often enables family members to stay nearby while also having independence.
Building an Attic Apartment
For Cara and Paul Gillis, converting their attic gave them one more reason to love their Victorian-era house, the home they have lived in for nearly 25 years while raising two sons. “We have now created a 700-square foot apartment for our older son in what was originally a dark, creepy attic, and everybody’s happy,” says Cara, who has worked hard over the years to care for the house’s original details—from plaster moldings and ceiling medallions to wood banisters and newel posts.
As much as they love their house and neighborhood, they are realistic about housing prices in Boston, so when their older son, Tom, graduated from college recently and began working, they saw firsthand the difficulty of finding an affordable place to live.
“We thought, why not build an apartment here,” recalls Cara, who worked with architect Owen Thomas and builder Gareth Barr for the renovation, which was documented by TOH TV’s Season 47.
Transforming a Dark Attic Into a Bright Loft
Accessed by a narrow staircase, the attic had been used for storage—with the family placing boxes, clothing, and old furniture on rough floorboards amid the ductwork and roof joists. The apartment they envisioned needed living and sleeping spaces, as well as a full bathroom, kitchen, washer-dryer, and separate entrance.
The architect’s plan emphasized an open loft concept, enlarging existing dormer windows and adding skylights to bring in as much natural light as possible, defining spaces through architectural features, and providing storage through built-ins.
Solving the Challenges of Small-Space Construction
The biggest challenge, in builder Gareth Barr’s viewpoint, was simply the constraints of square footage while bringing building materials and equipment in and out. “We were definitely tight for space,” he says. The work started with leveling all joists, framing kneewalls, adding closed cell insulation, laying a 5/8th inch membrane under the floor for noise reduction, and roughing in plumbing and fixtures throughout the space.
Given that the attic contained HVAC ductwork and mechanicals for the main house, a solution was needed to hide those elements and the HVAC unit for the new apartment. The answer was a strategically placed architectural feature in the living area in the form of an acoustic slat wood panel wall that not only hides the HVAC but also muffles the noise.
The sloped ceilings reflecting the house’s roofline helped define spaces within the apartment, with the bedroom tucked in one area and the living area occupying the largest open space. After the interior stairs were rebuilt, Barr’s crew made a custom wooden unit that wraps around the opening at the top of the stairs and creates a center island that also helps define the living area.
Inside the 700-Square-Foot Apartment
The apartment’s separate entrance is an exterior wooden stairway with metal balustrade at the rear of the house, with a door into the kitchen area. Deep closets just inside the back door function as a mudroom, with space for boots, shoes, and jackets.
The kitchen itself is a galley style layout, with the sink and cooktop wall featuring only base cabinets, for a minimalist look. The opposite kitchen wall features cabinets above and below the wall oven, plus additional countertop space.
White oak floors, white painted walls, and white tile in the kitchen and bath accentuate the light-filled loft, with black closet doors adding contrast. The overall effect is surprisingly spacious. Says Tom Gillis, who will live in the apartment: “There’s so much space here!”
TOH general contractor Tom Silva agrees: “This lives like a lot more than 700 square feet.”
How ADUs Support Multigenerational Living
For Tom, coming to this house had a flashback element—he had visited to fix a squeaky stairway and loose balustrade for an Ask This Old House segment 20 years ago, when Tom Gillis was just a toddler. “It’s fun to return, especially since the stairs and baluster are still in good shape,” says Tom.
Now that her much-loved 1895 house has a transformed top floor apartment, Cara Gillis has started imagining even more functionality—with thoughts of a second-floor apartment for her younger son, who is still in college. “We could have the entire family in this house, each with our own space,” says Cara in a nod to multigenerational living and one of the core reasons that ADUs are likely to continue growing in popularity.
For information about building an ADU on your own property, start by checking with your state and local governments.
