Sneak peek: We toured Wellesley’s first official Accessory Dwelling Unit

“The most important thing to do is communicate with your neighbors,” said Cynthia Sibold, the first Wellesley homeowner to receive construction approval for an Accessory Dwelling Unit (ADU) under an article approved by Town Meeting in April 2022. “We told our neighbors what we wanted to do, answered a lot of questions, and made sure we followed all the rules.”

A little bit of luck was involved, as well. About a year before ADUs were approved, Sibold had already made plans to tear down her rickety, detached two-car garage, which was tenanted by a robust population of squirrels. Sibold approached the town and asked about the possibility of doing exactly what she’s doing right now—building a new garage with about 700 square-feet of living area above. She and her husband, Bill, envisioned a snug space behind their main house. One with its own sleeping, cooking and sanitation facilities, perfect for visitors, or as temporary housing for any of their three adult kids, should they ever need a place to land as they looked for jobs and housing in the area. Sure, the squirrels would be disappointed, but family comes first, the Sibolds figured.

The town back then said yes to the new garage, but no to the plan for second-floor living space. The bylaws didn’t support the idea. Sibold sighed and started the permitting and design process for a new garage, sans living space above. Oh well, the second floor of the garage could be storage space. Who doesn’t need more storage space?

This is where the luck part comes in. Before the garage plans got to the point where change work orders became financially impractical, Sibold says she opened up her laptop to catch the latest town news on The Swellesley Report and saw this headline: Wellesley OKs accessory dwelling units.


“I’m never lucky with real estate stuff,” Sibold said. “Except this time.”

Since luck favors the prepared, she reviewed the town’s definition of an ADU—”an apartment within or on the same property as an owner-occupied, single-unit residential dwelling, that is subordinate to the main (or principal) dwelling unit”—and kicked into gear. In short order Sibold did that neighborhood communication thing, then applied for and received the necessary approvals (including a special permit from the Zoning Board of Appeals regarding setbacks). A particularly satisfying moment came when the ZBA expressed its unanimous opinion that the project as presented would not “disturb or disrupt the customary character of the residential neighborhood, and is in harmony with the intent and purpose” of the zoning bylaw that allows ADUs.

We were invited in for a tour of the work-in-progress. Take a look:

Accessory Dwelling Unit (ADU), Cynthia Sibold
Wellesley’s first Accessory Dwelling Unit is currently under construction in the space above the Sibold’s new two-car garage. The permitting process started Sept. 29, 2022, when Sibold requested a hearing in front of the Planning Board. On Nov. l, the Planning Board reviewed the petition and and recommended the Zoning Board of Appeals OK the special permit, which it did.


Accessory Dwelling Unit (ADU), Cynthia Sibold
A bluestone walkway to the right of the garage leads to the access door to the ADU. Duckham Architecture and Fallon Custom Homes are in charge of the project.


Accessory Dwelling Unit (ADU), Cynthia Sibold
ADUs are often referred to as in-law apartments. Proponents say they can also be be used as possible income for homeowners, such as those who could use the rental money they would generate to offset the high cost of living in Wellesley. For those who hope that ADUs might improve housing affordability and attainability, Wellesley Planning Board chair Jim Roberti said during last year’s Town Meeting that based on a review of other communities, we’re most likely looking at only three to five new ADUs per year. As the bylaws stand right now, most lots in town will unlikely be able to accommodate ADU structures due to insurmountable setback issues and other rules. However, with the approval of the units, the town seems to be signaling that it’s open to some creative thinking around Wellesley’s housing issues.

Accessory Dwelling Unit (ADU), Cynthia Sibold
A light-filled work-in-progress. The space will be a large studio apartment, with a galley kitchen and a small bathroom with a stand-up shower stall. ADUs may not exceed 900 sq. ft. in size and must comply with all other zoning, building, and health rules in town regardless of whether they are attached to an owner’s primary property. All ADUs require annual certification.


Accessory Dwelling Unit (ADU), Cynthia Sibold
Sibold hired a hydraulic engineer to ensure that the project didn’t cause water displacement headaches for either her or her neighbors. “It was so worth the money,” she said. “You have to be mindful of water and know your water patterns.” Stormwater runs down the sloped driveway and into a grate. From there, water is guided to and is filtered by a low-maintenance rain garden, reducing the amount of water running off-site.

If you’re interested in the possibility of constructing your own ADU, start your research with this town document that covers definitions, code compliance, and more, and review the Planning Department’s page on the Town of Wellesley website. Interim Planning Director Eric M. Arbeene said in an email, “We are still working on drafting the regulations and developing an appropriate application form.”

You can contact the Planning Department at or 781-431-1019, ext. 2232.

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