ADU Build Services · Greater Boston
We studied your property.
Now we can build it.
Your MA ADU handles the feasibility, design direction, and permitting strategy. Our sister company, Two Four Builders, a licensed Massachusetts general contractor, takes the project from permits through certificate of occupancy. One team, one honest path, no handoff to a stranger.
- By-right since Feb 2025
- Up to 900 sq. ft.
- Licensed & insured
- HIC #216967 · CSL #106789
Who does what
Two companies, one team.
We keep the advisory work and the construction work in separate companies on purpose, so the feasibility read you get is honest and the entity swinging hammers is fully licensed for it. Same people, clear roles.
Feasibility & Advisory
Your MA ADU
The free feasibility study, zoning review, cost and rent analysis, and design direction. Everything you need to decide whether to build, before you spend a dollar.
Construction
Two Four Builders
Our licensed general contracting company holds the construction contract and manages the build: permits, subcontractors, inspections, and certificate of occupancy.
What we build
Infill on tight lots is our specialty.
Greater Boston's dense neighborhoods are where ADUs are needed most, and where they're hardest to build. Nonconforming lots, tight setbacks, no crane access, century-old structures. That's the work we do, across three paths:
Conversions
The fastest, most cost-effective path, using space you already have.
- Basement apartments
- Attached & detached garage conversions
- Attic and internal carve-outs
- Grandfathered nonconforming structures, converted where nothing new could be built
Detached New Builds
A standalone backyard unit, designed for a small urban lot from day one.
- Backyard cottages up to 900 sq. ft.
- Setbacks, fire separation, and access planned up front
- Utility trenching, Dig Safe, service upgrades
Interior Units in Multifamily
Adding a unit inside a two-, three-, or four-family you already own.
- Interior ADUs in existing multifamily stock
- Scopes aligned to local zoning and code
- Rent comps and income analysis included in your study
Why build one
An ADU is a second home on your own lot. What it does for you is your call.
Income gets the headlines, but it's one of several reasons Massachusetts homeowners are building. The right answer depends on your family, your finances, and your next ten years, and the feasibility study looks at all of it.
Rental income
Add a rentable unit without buying more land, offsetting your mortgage or generating cash flow on a property you already own. Your study includes real rent comps for your street, not a statewide average.
Multigenerational living
House aging parents close enough to help, far enough for everyone's sanity. Or give an adult kid a real front door while they save. Private kitchen, bath, and entrance mean independence in both directions.
Aging in place & downsizing
Build a single-level unit now and stay on the property you love as stairs get harder. Some owners flip the script entirely: move into the ADU, rent the main house, and let the property fund the next chapter.
Home office & flex space
A detached studio that's a real workspace today can be a rental or in-law unit tomorrow. Building it as a code-compliant dwelling keeps every future use on the table.
10–20%
Typical ROI on cash invested we're seeing on MA ADU projects
$1,800–$3,000
Monthly rent range, internal units up to detached cottages
By Right
No special permit or public hearing on qualifying lots statewide
Figures reflect typical local market ranges and current MA law. Every property is different. Your feasibility study gives you numbers specific to yours.
How it works
Feasibility to finished unit.
The biggest ADU risk is finding out too late that your lot, utilities, or budget won't support the plan. We surface all of that up front, for free, before you commit to anything.
Free feasibility study
An in-person site visit and a professional written report: what your lot allows, which ADU type fits, real costs, rent comps, and financing paths. Free, with zero obligation to build with us.
Your MA ADUDesign & permit
Design aligned to your local zoning, then full permitting: service upgrades, trenching, Dig Safe, and the code pathway decided before anyone breaks ground.
Two Four BuildersBuild
One coordinated crew of vetted subcontractors under our licensed GC. Clear scope, clear schedule, clean job site, and regular communication through final inspection and certificate of occupancy.
Two Four BuildersRent or move in
A compliant, move-in-ready unit, plus broker-backed rent comps if you're renting it out. Whatever the ADU is for, it's ready for it.
Your MA ADUBuild questions
What homeowners ask first.
Can I build an ADU on my property in Massachusetts?
In most cases, yes. The Affordable Homes Act allows one ADU by right on single-family lots statewide as of February 2, 2025, with no special permit or public hearing required when the unit meets the standard criteria. Towns can still set reasonable rules on placement and design, but they can't ban ADUs outright. The first step is confirming your specific lot and town, which is exactly what the free feasibility study does.
How big can an ADU be?
Up to 900 square feet, or 50% of your main home's gross floor area, whichever is smaller. That's the by-right limit. Some towns allow larger ADUs through a special permit.
Do I have to live on the property?
No. Under the state law, municipalities cannot require owner-occupancy for by-right ADUs in single-family zones. That means you can buy a single-family, add an ADU, and rent both units, though some towns may require an extra parking space in certain cases. This is a major reason investors are paying attention.
What does an ADU cost to build?
It depends heavily on type and existing conditions. A basement or internal conversion with utilities already nearby is the most cost-effective path; a detached new build with trenching and a service upgrade sits at the higher end. Your feasibility study gives you a real line-item estimate for your property before you commit to anything.
How long does it take?
Conversions are typically the fastest. Detached new builds take longer because of foundation, utility, and permitting work. We lay out a realistic schedule during design so there are no surprises.
My garage sits right on the lot line. Can it still become an ADU?
Often, yes, and this is one of the biggest hidden opportunities in dense neighborhoods. A preexisting nonconforming garage already legally exists in a spot where today's setbacks would never allow new construction. Converting within that footprint can unlock a location a new build simply can't have. Every town reviews these on their own terms, which is exactly the kind of read your feasibility study gives you.
Can you help me find a property to add an ADU to?
Yes. With a licensed MA broker in-house through our affiliate Peak Realty Advisors, we can identify properties primed for ADU conversion and run the rent and equity comps before you buy.
See what your lot can do.
Tell us about your property and your goals. We'll start with the free feasibility study and give you the real cost, zoning, and income picture. No pressure, no guesswork.
Construction services are provided by Two Four Builders LLC, a licensed Massachusetts general contractor. MA Home Improvement Contractor Registration #216967 · Construction Supervisor License #106789. Your MA ADU provides feasibility and advisory services and does not perform construction.