ADU Contractors in Massachusetts
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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Home & Hearth Remodeling and Restoration
203 Circuit Avenue, West Springfield, MA 01089
Home & Hearth Remodeling offers ADU construction in Massachusetts. Since the 2024 Affordable Homes Act, homeowners can add one ADU by right in single-family zones. Services include detached ADUs, in-law suites, and garage conversions.
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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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New England Additions
809 Turnpike Street, North Andover, MA 01845
New England Additions, backed by Sordan Construction, offers pre-designed ADU builds across 25+ Greater Boston communities. Specializing in in-law suites and detached ADUs, they streamline permitting, budgets, and timelines for Massachusetts homeowners.
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Alcantara Construction
407R Mystic Avenue, Medford, MA 02155
Alcantara Construction is an experienced ADU contractor specializing in detached ADUs, garage conversions, JADUs, in-law suites, and granny flats. They guide homeowners through planning, permitting, and building accessory dwelling units efficiently.
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Horizon ADU
77 King Street, Boston, MA 02122
Trusted Boston ADU builders specializing in attached, detached, and two-story accessory dwelling units. Stick-built construction ensures code compliance and lasting value. Services include design, permitting, and full project management for multigenerational living or rental income.
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South Coast & Associates Inc
45 Slocum Road, Dartmouth, MA 02747
South Coast & Associates builds custom ADUs in Southeastern Massachusetts. From detached backyard cottages to garage conversions and in-law suites, they handle design, permitting, and construction for single-family homeowners.
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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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Auburndale Builders
151R Adams Street, Newton, MA 02458
Auburndale Builders completed an 800 sq ft ADU in Newton, MA—a single-level, universally accessible in-law suite with full kitchen, bathroom, bedroom & living area, built in compliance with local zoning regulations.
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Stella Home Services
25 Everett Street, Woburn, MA 01801
Stella Home Services is a Greater Boston ADU contractor specializing in basement apartments, garage conversions, in-law suites & home additions. They manage design, permitting & construction for fully functional accessory dwelling units.
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Luxe & Co Accessory Dwellings
60 Thoreau Street, Concord, MA 01742
Luxe & Co. Accessory Dwellings is a Massachusetts ADU builder offering full-service design, construction, and permitting. Founded by Hope Beckman and Sage Conti, they specialize in high-end ADUs including in-law suites, carriage houses, and home offices.
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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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Boston Building Concepts
275 Main Street, Watertown, MA 02472
ADUs are self-contained living spaces on existing properties. Legal in Massachusetts, local zoning rules apply. Boston Building Concepts is a Massachusetts ADU contractor offering full-service design, permitting, and construction of garage conversions, in-law suites, and detached ADUs.
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13 Gables Inc
64 Millbury Road, Worcester, MA 01540
13 Gables Inc, a licensed MA general contractor with 38+ years experience, builds custom ADUs including detached units, garage conversions & in-law suites. Massachusetts' 2025 Affordable Homes Act now allows ADUs by right in single-family zones.
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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, and chair lift for aging-in-place living.
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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.