What does accessory dwelling unit mean — Boston, MA

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.

About this service

An accessory dwelling unit is a secondary housing unit on a single-family residential lot. It can be attached to your home, like a basement apartment, or detached in your backyard. People ask this when they are starting to explore ways to increase their property's utility or income potential. It is essentially a complete living space with its own kitchen, bathroom, and entrance. Exact pricing confirmed free on the call.

Frequently asked in Boston

Also serving nearby: Quincy · Cambridge · Lynn · Newton · Brockton

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Boston — population 653,833; about 13,525 residents per square mile across 48.3 sq mi. ZIP codes covered include 02108, 02109, 02110, 02111, 02112, 02113, 02114, 02115.

Neighborhoods served in Boston: Back Bay, Beacon Hill, South End, North End, Jamaica Plain, Dorchester — and every surrounding area.