Accessory dwelling unit companies

Looking for accessory dwelling unit companies 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

These companies provide comprehensive support for homeowners, often pairing design experts with construction crews to handle the entire project under one roof. They are helpful when you want to avoid hiring separate architects and builders. You should look into these companies when you want a streamlined experience and a single point of accountability for your backyard project from start to finish.

Frequently asked in Boston

What are the disadvantages of ADUs?

How much does an ADU cost in Massachusetts?

The cost of an ADU in Massachusetts varies significantly based on size, materials, and site complexity. Factors like foundation work, utility hookups, and finishing details all play a role. Location within Boston and the specific neighborhood can also impact labor and material costs. Getting a personalized quote is the best way to understand the investment for your specific project.

What are the rules for ADUs in California?

California has state-wide ADU laws that streamline approvals, but local ordinances can still apply. Key rules often involve minimum lot sizes and setbacks from property lines. There are also guidelines on owner-occupancy requirements and parking. While this information pertains to California, understanding local Massachusetts regulations is crucial for your Boston project.

Is ADU allowed in Maryland?

Yes, ADUs are allowed in many areas of Maryland, with specific regulations varying by county and municipality. Maryland has been a leader in promoting ADUs to address housing needs. While this isn't directly about Boston, the general trend shows ADU adoption is growing, and local rules are key.

These programs aim to reduce the upfront financial burden of ADU construction. While this specific grant is for California, it highlights a trend of financial support for ADUs. It's always worth asking about any available incentives in Massachusetts when you call for your quote.

What are the rules for ADU in California?

California's ADU laws are designed to encourage their development, often by limiting local restrictions. Common rules include limitations on the size of the ADU and requirements for fire sprinklers. Many jurisdictions also have specific guidance on utility connections and parking. Understanding these rules is essential for any ADU project, though your focus should be on Boston's regulations.

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, South End, Beacon Hill, North End, Charlestown, Dorchester — and every surrounding area.