ADU Contractors in Massachusetts
DCCS Construction
74 Howland Street, Boston, MA 02121
DCCS Construction helps Boston homeowners navigate the ADU program, converting basements, attics, and existing spaces into independent rental units. Serving 1-3 family homes, they handle both architectural design and construction for full ADU proj... read more
Boston Deck Builders
Natick, MA
Boston Deck Builders offers ADU construction in Greater Boston, including detached, attached, and interior units. Services cover planning, permitting, and build. Costs range from $150K–$400K+. Prefab options available. Compliant with Massachuset... read more
Brittivia Homes & Construction
913 Northfield Road, Lunenburg, MA 01462
Brittivia Homes & Construction offers expert ADU construction in Middlesex, Worcester & Essex counties, MA. With 20+ years experience, they handle permits, garage conversions & in-law suites. Costs range $150–$300/sq ft.
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Turnkey ADUs
435 Lancaster ST, Leominster, MA 01453
Turnkey ADUs is a Leominster, MA ADU contractor offering modular, prefabricated accessory dwelling units across New England. Models range from $119K–$249,900. Massachusetts' 2024 Affordable Homes Act now allows ADUs up to 900 sq. ft. by right.read more
Republic Building Contractors
30 Log Bridge Road, Middleton, MA 01949
Republic Building Contractors is a full-service ADU contractor in Massachusetts handling design, permits, and construction under one roof. They build detached, attached, and garage conversion ADUs, with projects averaging 6–9 months.
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Design 1 Kitchen & Bath
363 Great Road, Bedford, MA 01730
Design 1 Kitchen & Bath designs and builds ADUs in Massachusetts, handling consultation, design, permitting, and construction. ADUs add rental income, multigenerational living space, and property value for Greater Boston homeowners.
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North Shore ADU Home Builders
Essex, MA 01929
North Shore ADU Home Builders LLC builds custom ADUs up to 900 sq ft across Massachusetts. Services cover design, permits & construction. Rental income ranges $1,800–$3,500/month. Property values may rise $100K–$250K.
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Regulus Construction
36 West Street, Milford, MA 01757
Regulus Construction is a licensed ADU contractor serving MetroWest Massachusetts. They build detached backyard cottages, garage conversions, and in-law suites, managing design, permitting, and construction across 40+ towns.
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Salisbury Construction Worcester
453 Chandler Street, Worcester, MA 01602
Salisbury Construction Worcester builds ADUs across Worcester County, Central Mass & MetroWest. Services include detached units, garage conversions, basement conversions & home additions using a streamlined design-build process.
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Penfield & Sons Inc.
326 Chapman Street, Greenfield, MA 01301
Penfield & Sons, Inc. is a family-owned contractor in Greenfield, MA, serving Western Massachusetts since 1970. They offer roofing, insulated vinyl siding, and replacement windows, delivering quality residential renovation services.
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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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Steveworks LLC
108 Cabot Street, Newton, MA 02458
Steveworks LLC completed a whole house remodel in Newton, redesigning the floor plan, replacing windows, siding, and roofing, and upgrading insulation. They also built an accessible ADU above a garage, featuring a full kitchen, curbless shower, an... read more
Pro's Edge Small Homes
27 Pillsbury Street, Georgetown, MA 01833
Pro's Edge Small Homes is a licensed ADU contractor in MA & NH with 20+ years experience. They offer turnkey design, permitting & modular construction of granny flats, in-law suites & backyard cottages, including a free property evalua... read more
Avalon Building Systems
560 Turnpike Street, Canton, MA 02021
Avalon Building Systems builds custom modular homes and ADUs across the northeastern US. A VA Certified Builder, they offer turnkey services, Energy Star-compliant construction, and compact floor plans like in-law suites and backyard cottages.
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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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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.