Basement Conversion in Massachusetts

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.

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.read more

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.

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 contrac... read more

Core Remodeling Services has built ADUs and in-law suites across Central Massachusetts since 2012. They handle zoning, permits, design, and construction. Projects range from $150K–$400K+, take 6–8 months, and are backed by a 5-year warranty.read more

Ruhan General Contracting LLC builds home additions and ADUs in North Attleboro, MA. Services include room additions, in-law suites, second-story additions, and detached ADUs, covering permits, design, and finish carpentry throughout Massachusetts... read more

Baystate Group Builders Inc offers residential remodeling services including basement finishing, bathroom renovations, deck construction, carpentry, and painting. Led by Victor, the team is known for professionalism, clear communication, and quali... read more

Beantown Builders, Inc. is a Greater Boston ADU contractor offering full-service design, permitting, and construction. Projects include detached ADUs, garage conversions, and in-law suites, with budgets from $15,000 to $1M+.

Planning an ADU in Massachusetts? Costs range from $250–$500+ per sq ft. State law now allows ADUs by right on single-family lots. Learn about permits, the Stretch Energy Code, and working with a qualified ADU contractor in Greater Boston.

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 zone... read more

Massachusetts' new ADU legislation allows homeowners to build detached or attached accessory dwelling units. CZ Construction Management LLC helps with planning, permits, and construction of ADUs across Massachusetts, including Greater Boston.

John Crowley Construction Co offers turnkey ADU construction on Massachusetts' South Shore, serving Pembroke, Plymouth, Hingham & more. Licensed (#114197), insured, 25+ years experience. Detached, attached, garage & basement ADUs available... read more

ADU Of Massachusetts is a full-service ADU builder specializing in design, permitting, and construction of accessory dwelling units. Serving homeowners statewide, they build attached, detached, garage conversions, in-law suites, and backyard cotta... read more

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.

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.