Accessory dwelling unit contractor

Looking for accessory dwelling unit contractor in Boston, MA? Call AccessoryDwellingUnit Services for a contact a provider — no obligation. Licensed adu builders serve Boston and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

About this service

A contractor oversees the physical build, managing the subcontractors, materials, and daily construction progress. They are responsible for making sure the structure is built according to the approved plans and local safety standards. You need a contractor when you have your designs finalized and are ready for the actual building phase to begin. They act as the primary point of contact for all site activity.

Frequently asked in Boston

What are the disadvantages of ADUs in Boston?

While ADUs offer many benefits, potential disadvantages in Boston can include initial construction costs and navigating the city's specific building codes and zoning regulations. It's also important to consider how an ADU might impact your existing property's yard space or privacy. Understanding these factors upfront is crucial.

How much does an ADU cost in Massachusetts?

The cost of an ADU in Massachusetts varies significantly based on size, materials, and site preparation needed for your Boston property. Factors like foundation type, complexity of plumbing and electrical work, and finishes all play a role. A detailed quote from a local pro will give you the most accurate picture for your specific project.

What are the rules for ADUs in California?

California has specific regulations regarding ADU development, often allowing them by right with streamlined permitting processes. These rules typically cover minimum lot sizes, setback requirements, and restrictions on owner occupancy. If you're considering an ADU in California, it's essential to check the latest state and local ordinances.

Is ADU allowed in Maryland?

Yes, ADUs are permitted in many areas of Maryland, including Baltimore. Local zoning ordinances will dictate specific requirements such as size limitations, setback distances, and parking provisions. It's important to consult your local planning department for the exact rules in your area.

What are the rules for ADU in California?

California's ADU laws are designed to encourage their development, often allowing them as a permitted use in residential zones. Key rules include limitations on owner-occupancy requirements for some ADUs and statewide standards for setbacks and height. Always verify with your specific city or county's planning department.

California has offered various grant programs to help homeowners build ADUs, including initiatives that provide financial assistance. These programs often have specific eligibility criteria related to income and the type of ADU being built. Information on current grants can usually be found through state housing agencies or local ADU resources.

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

653,833residents

13,525per sq mile

8ZIP codes served

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, Dorchester, Allston — and every surrounding area.