ADU Contractors in Massachusetts
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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MBA Builders
500 Edgewater Drive, Wakefield, MA 01880
Massachusetts ADUs are now legal by right statewide after 2024 legislation. MBA Builders offers full-service ADU construction across Greater Boston, with structured preconstruction planning and builds starting around $450/sq ft.
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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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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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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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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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Amex Construction
15 Industrial Way, Hanover, MA 02339
Amex Construction is a Hanover-based design-build ADU contractor serving Massachusetts' South Shore. They manage detached ADUs, barn conversions, and basement suites, handling design, permitting, septic upgrades, and construction under one contract.
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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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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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Massachusetts Adu Plans
68 Harrison Avenue, Boston, MA 02111
Massachusetts homeowners can get permit-ready ADU plans starting at $800, delivered in days. Three tiers cover plans, cost estimates, and full custom design up to $3,100. Free ADU Starter Guide available.
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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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Woodland Builders
195 Hanover Street, Hanover, MA 02339
Woodland Builders is a full-service ADU builder serving South Shore, MA, including Hingham, Plymouth & Scituate. They manage design through construction, ensuring quality, compliance, and streamlined project management for accessory dwelling units.
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BuildX- Your Building & ADU Experts
1 Marion Drive, Carver, MA 02330
BuildX is a trusted ADU contractor in Southeastern Massachusetts with 40+ years of experience. They offer custom stick-built accessory dwelling units, granny flats, and in-law suites with a 100-day build guarantee and transparent pricing.
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ADU-PRO Corp.
121 Orchard Street, Millis, MA 02054
ADU-PRO Corp is a Massachusetts ADU specialist offering full-service construction, permitting, and project management. Led by licensed experts, they help homeowners build granny flats, in-law suites, and backyard cottages up to 900 sq ft.
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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.