An accessory dwelling unit is a second, smaller, self-contained home on the same lot as your house, with its own kitchen, bathroom, and entrance. In Quincy, an ADU can be a detached backyard cottage, a garage conversion, a basement apartment, or an addition, and homeowners use them for aging parents, adult children, or rental income.
A typical JRH ADU in Quincy includes:
The process starts with a free in-home consultation to look at your lot, your goals, and which ADU type fits. JRH handles the design, confirms it against the state law and Quincy zoning, and files the ADU and trade permits through the City of Quincy. We build the unit, coordinate the licensed electrician and plumber, and finish with inspections and a certificate of occupancy.
Yes. Building an ADU in Quincy requires permits, but the process is now far more predictable. As of February 2, 2025, the Massachusetts by-right ADU law allows ADUs of up to 900 square feet by-right in single-family zones statewide, without a special permit or discretionary approval. You still need a building permit plus separate electrical, plumbing, and gas permits from licensed trades.
JRH files the ADU permit through Quincy’s online permitting system (ViewPoint Cloud), which has a dedicated Accessory Dwelling Unit application, and manages the inspections through to a certificate of occupancy. We confirm setbacks, egress, and utility connections up front so the project stays by-right. Inspectional Services: (617) 376-1450.
In Massachusetts, most ADUs cost between about $200,000 and $400,000, or roughly $275 to $450 per square foot for detached new construction (2026 data). A compact 400 square foot unit can run about $110,000 to $180,000, while a full 1,000 square foot ADU can reach $275,000 to $450,000. Garage and basement conversions are often less, since the shell already exists, though they still need insulation, egress, and code upgrades. Energy-efficient ADUs may qualify for Mass Save rebates, and JRH is covered by the state’s Home Improvement Contractor program and Guaranty Fund. Every estimate is free and itemized.
JRH builds ADUs throughout Quincy, including Quincy Center, Wollaston, North Quincy, Squantum, Marina Bay, Merrymount, Houghs Neck, Adams Shore, West Quincy, Quincy Point, Montclair, and Germantown.
Quincy sits in Norfolk County and covers ZIP codes 02169, 02170, and 02171. With high housing demand near the Red Line, ADUs are a practical way for Quincy homeowners to add multigenerational space or rental income. JRH is a licensed and insured Massachusetts home improvement contractor (MA HIC #204867) serving all of these neighborhoods from nearby Lynn.
Because JRH is a registered Massachusetts Home Improvement Contractor (#204867), your ADU in Quincy is covered by the state’s consumer-protection framework, and we permit and inspect every stage through the City of Quincy. Below are the questions Quincy homeowners ask us most.
