Beantown Builders, Inc. — ADU Contractor Serving Greater Boston
Beantown Builders, Inc. is a design-build construction firm based in Massachusetts, offering full-service accessory dwelling unit (ADU) construction for residential property owners throughout the Greater Boston area. As an experienced ADU contractor and accessory dwelling unit builder, they manage the entire process — from initial design through permitting and construction — under one roof.
The company brings over 40 years of combined construction experience to each project. Their licensed team handles design, permits, and build execution while ensuring compliance with local zoning regulations and Boston's ADU requirements. Projects range from detached ADU builds and garage conversion work to basement conversions and attached units.
ADUs built by Beantown Builders can serve a variety of purposes, including guest accommodations, rental units, private workspaces, or flexible living arrangements for family members. Whether a homeowner is looking for a granny flat builder, an in-law suite builder, or a contractor for a backyard cottage, Beantown Builders offers a structured process to help property owners understand their options before committing to a full project.
How the ADU Process Works
Beantown Builders begins each ADU project with a free discovery call. This initial conversation is used to understand the homeowner's goals, discuss realistic planning ranges, and determine whether the project is a suitable fit. No detailed pricing or design work begins at this stage.
Qualified projects then move into a paid on-site consultation and feasibility review. During this phase, the team evaluates existing site conditions, identifies potential risks, and refines the project scope before any design or detailed cost planning begins. This structured approach is intended to set realistic expectations early in the process.
Their core ADU services include:
- Custom ADU design and layout planning
- Full-service permitting and regulatory compliance
- Complete project management from start to finish
- Consistent construction quality throughout the build
For homeowners who do not yet have architectural plans, Beantown Builders can connect them with a design partner to guide concept development, revisions, and permit-ready drawings. Property ownership is required before an estimate can be provided.
Project budgets typically range from $15,000 to over $1 million, depending on scope and complexity. A simple basement or garage conversion may take a few months, while a fully detached ADU with new utilities and foundations can take considerably longer. The permitting process in Boston also adds time to the overall schedule.
ADU Regulations in Boston
Most single-family homeowners in Boston are eligible to build an ADU, though eligibility depends on zoning regulations, lot size, and design constraints. Boston has updated ADU pilot programs in certain neighborhoods, and rules vary by area. Beantown Builders manages all permitting to ensure each unit meets local requirements.
The city allows attached, detached, and basement or garage conversion ADUs in certain zoning districts. The team can help determine which type of ADU is most appropriate for a given property.
Beyond new construction, an ADU can add meaningful value to a property — both in terms of resale potential and long-term flexibility. Many homeowners use ADUs to house family members, generate rental income, or reduce living expenses over time.
Beantown Builders serves clients across Boston, Brookline, Somerville, Cambridge, Quincy, Newton, Waltham, Lowell, Lawrence, Lynn, Haverhill, Framingham, Taunton, and surrounding communities throughout Massachusetts. The firm is led by Donald S. Donnalson, Esq., a licensed attorney, second-generation general contractor, and real estate broker with over two decades of experience in Massachusetts construction and development.
