ADU Contractors in Massachusetts
Bethoney Builders LLC
56 Depot Street, Duxbury, MA 02331
Bethoney Builders LLC is a South Shore residential contractor specializing in ADU construction, home additions, custom builds, and renovations. Services include in-law suites, garage conversions, finished basements, and structural repairs.
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Hawthorn Builders
97 Chapel Street, Needham, MA 02492
Hawthorn Builders offers end-to-end ADU construction, managing consultation, design, permitting, and building. As a detached ADU and garage conversion contractor, they complete accessory dwelling units in ~90 days with minimal disruption.
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Bradford Construction Management
145 South Main Street, Haverhill, MA 01835
Bradford Construction Management brings commercial-grade project management to every ADU we build across the North Shore. That means daily photo documentation so you always know what's happening on site, transparent pricing so there are no budget surprises, and a clear schedule with real milestones.
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House Improvement LLC
6 Garfield Avenue, Shrewsbury, MA 01545
House Improvement LLC builds fully insulated ADUs with electricity and climate control, ideal for home offices or studios. They also construct storage sheds, carports, gazebos, and pergolas for diverse residential outdoor needs.
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Think ADU
123 Main Street, Worcester, MA 01608
Think ADU is a California ADU contractor specializing in design, permitting, and construction of accessory dwelling units. Services include detached ADUs, garage conversions, JADUs, granny flats, and in-law suites for rental, family, or property value goals.
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River City Boston
9 Illinois Avenue, Somerville, MA 02145
River City Construction is a Boston-based ADU contractor specializing in home additions, garage conversions, in-law suites & detached backyard cottages. They manage design, permitting & full construction under one roof.
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Aureli Construction
Eugene Road, Medford, MA 02155
An Accessory Dwelling Unit (ADU) is a self-contained living space on a residential property. Massachusetts law now makes ADU construction easier. Aureli Construction offers full-service ADU building, from zoning research to completed construction.
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Top Pro Inc.
35 Bradshaw Street, Medford, MA 02155
Top-Pro Construction, Inc. is Greater Boston's trusted ADU builder with 25 years of experience. Specializing in detached ADUs, attached units, garage conversions & basement ADUs to boost property value and rental income.
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Studio Luz Architects
4238 Washington Street, Boston, MA 02131
Studio Luz Architects designed a 1,180 sq ft attached ADU featuring solar power, wind energy, energy recovery systems, and water collection. The sustainable addition boosted property value while serving as a functional secondary living space.
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ADU Building Systems, LLC
Norwell, MA 02061
ADU Building Systems LLC builds factory & site-built ADUs in Massachusetts, including detached, attached & converted units. Offering 10-year structural warranties, cost savings up to 50%, and full-service design to turnkey construction.
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Yeoman Design Build
123 Sandgully Road North, Shelburne Falls, MA 01373
Yeoman Design Build specializes in sustainable Accessory Dwelling Units (ADUs) in Massachusetts. From detached ADUs to granny flats and in-law suites, they offer holistic design, careful materials selection, and full project management for property owners.
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New England Outdoor
37 Oakland Avenue, Methuen, MA 01844
New England Outdoor, a family-owned business in Methuen, MA, builds custom sheds, garages, pavilions, and ADUs across New England. Specializing in ADU construction, garage conversions, and in-law suites, they handle design, permits, and zoning guidance.
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Walczak Design and Build LLC
25 South Main Street, Ipswich, MA 01938
Walczak Design and Build LLC is a trusted ADU contractor on Massachusetts' North Shore, serving Ipswich, Newburyport, Beverly & more. They offer full-service ADU design, permitting, and construction with transparent planning and expert project management.
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Atlantic Property Development
444 Broadway Unit B #1069, Saugus, MA 01906
ADUs are now legal statewide in Massachusetts. Atlantic Property Development builds custom Accessory Dwelling Units on the North Shore, offering design, permitting, and construction services for detached, attached, and garage conversion ADUs.
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Boston Construct
1660 Soldiers Field Road, Boston, MA 02135
Boston Construct is a full-service ADU contractor in Boston, MA, building basement conversions, garage conversions, detached backyard cottages, and in-law suites. They handle design, permitting, and construction for 1-3 family homeowners across Greater Boston.
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Other cities in Massachusetts
What you need to know
ADU Contractors in Massachusetts: Navigating the 2024 Zoning Reform
Massachusetts made a landmark move in 2024 when Governor Maura Healey signed the Affordable Homes Act, a sweeping housing reform that significantly changed how Accessory Dwelling Units (ADUs) are handled across the state. Under this legislation, ADUs are now allowed by-right in single-family zoning districts statewide, meaning homeowners no longer need special permits or variances in most cases. This makes Massachusetts one of the more progressive states for ADU development, and experienced ADU contractors in Massachusetts are in high demand to help homeowners take advantage of these new opportunities.
What Massachusetts ADU Contractors Do
ADU contractors in Massachusetts specialize in designing, permitting, and building accessory dwelling units, which can include basement conversions, garage conversions, detached backyard cottages, and attached in-law suites. These professionals are well-versed in the state's building codes, local zoning bylaws, and the specific requirements set by the Massachusetts State Building Code (780 CMR). A qualified ADU contractor will guide homeowners through every stage of the process, from initial design to final inspection.
Key Regulations Massachusetts ADU Contractors Must Follow
Even with the statewide by-right allowance, ADU contractors in Massachusetts must still navigate several important regulations, including:
- Size limitations: ADUs must generally not exceed 900 square feet or half the square footage of the primary dwelling, whichever is smaller, under the Affordable Homes Act guidelines.
- Owner-occupancy rules: Municipalities may impose owner-occupancy requirements, though the state has limited how restrictive these can be.
- Setback and lot coverage requirements: Local zoning bylaws still govern setbacks, height limits, and lot coverage, which vary by municipality.
- Utility connections: ADUs must meet Massachusetts plumbing, electrical, and energy codes, including compliance with the Massachusetts Stretch Energy Code in many communities.
- Historic districts: In cities like Boston, Salem, or Nantucket, ADU projects may require additional review from local historic commissions.
Choosing the Right ADU Contractor in Massachusetts
When selecting an ADU contractor in Massachusetts, homeowners should look for professionals who hold a valid Massachusetts Construction Supervisor License (CSL) and carry proper liability and workers' compensation insurance. Experience with local permitting offices is a major advantage, as requirements can differ significantly between cities like Boston, Worcester, Springfield, and Cambridge. Ask for references from completed ADU projects and verify that the contractor is familiar with both state and local regulations.
The Value of Building an ADU in Massachusetts
With one of the highest housing costs in the nation, Massachusetts homeowners have strong financial incentives to build ADUs. A well-constructed ADU can generate rental income, increase property value, and provide housing for aging family members. Working with a knowledgeable ADU contractor ensures your project is completed efficiently, legally, and to the highest standards, making your investment worthwhile for years to come.