ADU builder for Northern MA & Southern NH
Detached cottages, garage conversions and in-law suites. Both states now allow ADUs by right, and Massachusetts is funding them. We handle the whole thing, from zoning check to move-in.
The rules changed in your favor
In the last two years both states took away most of the zoning hurdles that used to stop ADU projects.
Massachusetts
- ADUs up to 900 sq ft (or half the main house, if smaller) are allowed by right in single-family zones under the Affordable Homes Act.
- MassHousing ADU loans: second mortgages up to $250,000 for eligible homeowners. masshousing.com/adu
- MHP ADU Incentive Program: state-funded feasibility studies, with a financial assistance phase announced October 2026.
- Free state ADU designs and a lot lookup tool at mass.gov/adu and MyMassADU.org.
New Hampshire
- Every town must allow at least one ADU, attached or detached, wherever single-family homes are allowed (RSA 674:71–73).
- Towns can't cap an ADU below 750 sq ft; the default maximum is 950 sq ft.
- Existing garages and outbuildings can be converted, and towns can't require the occupant to be related to you.
- Guide and resources from New Hampshire Housing at nhhousing.org.
Programs, eligibility and local bylaws change. This is general information, not legal or financial advice. We confirm what applies to your lot and town before you commit.
ADUs for how you want to live
Detached Cottage
A standalone home in the backyard for parents, adult kids, guests or rental income.
Garage Conversion
Turn an existing garage or barn into a finished apartment, often the fastest path.
Attached In-Law Suite
An addition with its own entrance, kitchen and bath, connected to the main house.
Modular ADU
Factory-built units set on a new foundation for a faster, more predictable schedule.
See a finished Palmer ADU in person
We're putting the final touches on our newest ADU. Before it's handed over, we're holding a small number of private walkthroughs for homeowners thinking about building one.
See the layout, the finishes and the millwork up close, ask about cost and permitting, and get a feel for what fits on your lot. Spots are limited; we'll email the date and address to people on the list.
From "can I?" to move-in
Lot & zoning check
We review your lot, your town's rules, setbacks and utilities to confirm what you can build.
Design & estimate
Layout options, renderings and an itemized estimate so you can choose with real numbers.
Financing & permits
We prepare permit drawings and documents and work with your lender or state program.
Build
Site work, foundation, utilities and construction, with job-day text updates.
Finish & move in
Custom cabinetry and trim from our millwork shop, final inspection and walkthrough.
ADU FAQ
Can I build an ADU on my property in Massachusetts?
Most likely. Under the Affordable Homes Act, Massachusetts allows one ADU by right on lots in single-family zoning districts, with no special permit needed. The protected size is up to 900 square feet or half the size of the main house, whichever is smaller. Towns can still apply reasonable rules on things like setbacks and site plan review, so we check your lot and your town's bylaw before you spend money on design.
Can I build an ADU in New Hampshire?
Yes. New Hampshire law (RSA 674:71–73) requires towns to allow at least one ADU, attached or detached, wherever single-family homes are permitted. Towns cannot cap an ADU below 750 square feet, and the default maximum is 950 square feet unless the town allows more.
Are there grants or financing for ADUs?
In Massachusetts, yes. MassHousing offers second-mortgage ADU loans of up to $250,000 to eligible homeowners, and the Massachusetts Housing Partnership runs an ADU Incentive Program that pays for feasibility studies, with a financial assistance phase announced in October 2026. Eligibility rules apply and programs change, so we point you to the current details at the start and work with your lender or program on draw schedules.
How much does an ADU cost?
It depends on size, detached versus attached, site work, utilities and finish level. After a site visit we give you an itemized estimate, so you can compare options like a garage conversion against a new detached cottage before committing.
How long does an ADU take to build?
Timelines depend on permitting in your town and the type of build. Modular ADUs can shorten the time on site considerably. We give you a schedule with your estimate and keep you updated by text on work days.
Can I rent out my ADU?
In both states ADUs can generally be rented, and New Hampshire towns cannot require that the occupant be related to you. Some towns have rules on short-term rentals or owner occupancy, which we check during feasibility.
Do you build modular ADUs?
Yes. We build ADUs with modular units as well as site-built. Modular units are built in a factory while we prepare the foundation and utilities, which keeps the schedule predictable. We will tell you which approach makes sense for your lot.
What does Palmer Innovative handle?
Everything from the feasibility check through permits, site work, foundation, utilities, the build itself and finish work, including custom cabinetry and built-ins from our millwork division.
