What does the permit set include?
- A site plan based on a survey, showing setbacks and the ADU's position.
- Floor plans, elevations and sections.
- Structural drawings, and engineering where the design needs it.
- Energy code documentation, which for new construction can include home energy rating modeling.
- Fire separation and egress details.
Will my town hold a public hearing?
Usually not for a protected-use ADU. As of October 2026, state guidance says a town cannot require a special permit or other discretionary zoning approval for the use or rental of a protected-use ADU, though it may use site plan review and apply its setback, bulk and height rules. A larger unit, or one that needs a setback reduction, can still go to a special permit: Brookline, for example, allows up to 950 sq ft that way.
How does it work in the City of Boston?
Boston's ADU program has described a long-form building permit filed with Inspectional Services, with Zoning Board of Appeal relief where a design needs it. Boston's ADU guidebook designs are not pre-approved plans, according to the Planning Department, so every project still goes through the normal review.
What if my house is in a historic district?
Newton, Brookline and Boston all have historic districts. Exterior work there can need a historic commission review in addition to the building permit. We check this at the lot check, because it can shape the design.
What do design and permits cost?
One Massachusetts ADU builder quoted in Banker & Tradesman (August 2026) put a site survey at $7,000 to $10,000, building permit fees at $750 to $5,000 depending on the municipality, energy rating modeling at $1,200 to $1,500 and ADU plans at $1,500 to $5,000. MassCEC estimates design, engineering, surveys and permits together at about 10 to 20 percent of the total budget. Your quote breaks these out line by line.
Who is licensed to do this work?
Massachusetts uses a Construction Supervisor License for supervising most structural building work and Home Improvement Contractor registration for many projects on existing homes. ADU Craft Boston is licensed and insured, and we put our license and insurance details in writing with every quote.
How long will permitting take?
It depends on the town, the type and whether anything goes to a board. A by-right interior unit with a complete first submittal is the shortest path. A Boston project that needs zoning relief, or a detached unit in a historic district, has more steps. We give you a schedule specific to your address with the quote.
Related
As of October 2026. Sources: Mass.gov ADU guidance; Town of Brookline Article 14 vote (May 2026); Boston Planning Department; City of Boston ADU program; Banker & Tradesman, "What Does It Cost to Build an ADU in Massachusetts?" (August 2026); MassCEC.
Ready for drawings?
Start with a lot check. Send the address and we confirm the zoning path before design begins.