ADUs (Accessory Dwelling Units) and In-Law Suites in Melrose and the Northern Boston suburbs
A second space designed for aging parents, a returning adult child, or long-term rental income, built to the new Massachusetts ADU law and the realities of your lot
A New Kind of Project for Massachusetts Homeowners
Massachusetts passed a statewide ADU law that meaningfully expanded what homeowners can build on their own property, and families across the Northern Boston suburbs are finally acting on plans they had been sitting on for years. An above-garage suite for aging parents. A basement conversion for an adult child coming home after college. A detached unit that helps carry the mortgage. PEGASUS Design-To-Build designs and builds Accessory Dwelling Units (ADUs) and in-law suites the same way we approach a home addition, which is the correct framing for the work, because an ADU is effectively a complete small home built into or onto your existing property.
There is one important distinction between an ADU and an in-law suite. ADUs are capped at 900 square feet under Massachusetts law and are fully independent dwelling units with their own kitchen. In-law suites have no size cap, but by code they cannot have a fully separate cooking facility and cannot be closed off from the rest of the main house. Which path makes sense depends on how the space will be used. We will walk you through both in the discovery conversation.
A good ADU or in-law suite does not feel like an afterthought. The kitchen or kitchenette is actually functional. The bathroom is sized for daily use, not quick visits. The bedroom has real light and a real closet. Exterior design matters more on ADUs than most homeowners expect: the unit has to read as part of the property, not as a separate building dropped onto it. Matched siding, proportionate windows, and a roofline that belongs to the main house are what make a detached or above-garage ADU look like an intentional extension of the home rather than a rental property.
How Our Design-Build Process Fits an ADU Project
ADUs are compact but complex. Zoning, code, utilities, and design all need to be resolved before construction starts. Our process is built for exactly that. Feasibility comes first, and it is specific to your lot, your town, and the current state of Massachusetts ADU law. Our Architectural Designer leads design through conceptual drawings and a budgetary estimate built on allowances. After you sign the construction Letter of Intent, our engineering partners produce stamped structural drawings, and the same designer carries you through finish selections and a permit-ready set of construction documents.
Once construction starts, your ADU runs with a dedicated project manager and daily communication on what is happening on site. Because ADUs often involve utility connections, separate metering, and accessibility considerations that a straight addition does not, we plan those details during pre-construction and confirm them with the town before we break ground.
Common Questions About ADUs and In-Law Suites
- How long does an ADU or in-law suite take to build?expand_more
- An in-place ADU with no foundation or addition work typically takes three to four months of construction once we break ground. ADU projects that involve an addition or new foundation typically take four to six months. Design and pre-construction add time on the front end and depend on the type of unit, your lot conditions, and your town's permit process. We confirm the full schedule with you before signing the construction agreement.
- What did the new Massachusetts ADU law change?expand_more
- The 2024 Massachusetts ADU law allows homeowners in most municipalities to build one accessory dwelling unit by right on a single-family lot, without needing a special permit or variance. This removed one of the biggest barriers to ADU construction in the state. Local zoning still applies for setbacks, lot coverage, and design standards, but the approval process is significantly simpler than it was before.
- What types of ADUs do you build?expand_more
- We build above-garage, basement conversion, and detached ADUs depending on your lot, your goals, and what the zoning will support. We assess feasibility early in the discovery process so you know what is actually possible before design begins.
- How is an ADU different from an in-law suite?expand_more
- Two things to know. ADUs are capped at 900 square feet under Massachusetts law and are fully independent dwelling units with their own kitchen, bathroom, and living space. In-law suites have no size cap, but by code they cannot include a fully separate cooking facility and cannot be closed off from the rest of the main home. We build both, and the right choice depends on how you intend to use the space and who will be living there.
- How does permitting work for an ADU in Massachusetts?expand_more
- We handle the permitting process as part of the project. Under the new ADU law, most by-right ADUs do not require a special permit, but building permits and inspections still apply. We manage the submission and coordination with the local building department. Timelines vary by town.
- Do you offer a warranty?expand_more
- Yes. We provide a one-year limited warranty on our labor and materials.
Our Design-Build Process
Every project starts with a conversation. We come alongside you to understand your vision, your home, and your investment range, then align on scope and priorities before any drawings begin.
What a well-designed ADU usually includes:
WHAT AN ADU OR IN-LAW SUITE COSTS IN MELROSE AND THE Northern Boston suburbs
ADU costs vary significantly by type. A 900 square-foot in-place ADU costs very different money than a detached new-construction unit. The ranges below reflect the most common ADU and in-law-suite types we build. These are project totals including design, permits, labor, and materials. ADUs are capped at 900 square feet by Massachusetts law; in-law suites are uncapped but cannot have a fully separate kitchen or be closed off from the main home.
In-Law Suite (uncapped square footage)
An attached space larger than 900 sf, by code without a fully separate kitchen and without being closed off from the main house.
Want the Full ADU Cost Breakdown?
ADU pricing depends heavily on your specific lot, your town's zoning, and the type of unit you are building. Our Cost Guide walks through the key cost drivers so you know what questions to ask before the first conversation.
Where We Build
PEGASUS Design-To-Build specializes in high-quality residential design-build projects throughout Melrose and the greater Northern Boston suburbs (including Arlington, Winchester, Stoneham, Wakefield, Saugus, Lexington, Belmont, Reading, and Medford.
Don't see your town?
Our Service Area
- Melrose
- Arlington
- Winchester
- Stoneham
- Wakefield
- Lynnfield
- Saugus
- Lexington
- Belmont
- Reading
- Medford
- Malden
In Our Clients' Words
They did excellent work for us in a redone basement and bathrooms ~4 years ago. Still holding up brilliantly!
Liz Lehtonen
Pegasus did a first floor addition to our home which included a primary bedroom, spacious closet, three piece bathroom, and pantry space. I cannot say enough positive things about working with this company! They made our vision come to life (thanks Jenna!) in a tight space. Start to finish everyone we interacted with was personable, highly skilled, and responsive. The project was completed on budget and quicker than the initial time projection. We lived in the home with two toddlers and a dog during the construction (while also working from home) and it was truly minimally disruptive to our daily routines. We received daily emails on the progress of the work which was so helpful (Mike is the best!). The space is gorgeous and makes me feel like I'm living in a fancy hotel. They are the best contractors I have ever worked with! I would highly recommend them!
Lara Rubinstein
Pegasus was awesome. Their communication was prompt and pleasant, we loved working with them. Our kitchen came together beautifully and they planned a beautiful space for us to live in!! Jenna is both an artist and a genius. We loved her design!
Jenni Somers
We absolutely loved every step of the home renovation process with Pegasus. We had our kitchen redone, and they had great ideas on layout and materials. They were extremely organized and communicative, and every member of their staff that we interacted with was professional and wonderful to work with. And we love our new kitchen. We would gladly seek them out for future work, and highly recommend them.
Paula Kulis
We had an amazing experience with Pegasus. We completed a kitchen remodel and mudroom/master bath/closet addition. They were on time, on budget, and so nice to work with. Every single person on the team was wonderful, and now we're living in our dream home!
Erin Molloy
Pegasus Contracting recently completed a kitchen renovation for me, and from start to finish they were absolutely wonderful to work with. They provided great recommendations and advice at the beginning around all the aspects - design, cabinets, tile, counter, flooring, lighting, appliances. The quality of the work throughout was excellent, their team is very experienced, dedicated, and respectful. I was tremendously grateful for the daily communication from the project manager; what a difference it made when living through a renovation to be kept informed on progress and what was planned for the next day. With highly skilled workers and expert coordination of all the phases of the project, my kitchen was completed exactly on timeline. Wow!
Helen
Working with Pegasus was a great experience. We were very nervous about doing a major renovation due to the bad experiences of other family members we have, but Pegasus guided us through the entire process. Jenna was fantastic working with us on design options and once construction got underway, Mike provided us with daily e-mail updates so we knew exactly what was going on.
No renovation project is going to be totally smooth, but Pegasus takes a lot of stress out of the process. I'd happily recommend them to anyone else seeking to do a home improvement project.
Dan Magazu
Considering an ADU or In-Law Suite?
Let's look at what your lot will support
Tell us a little about your property, who the space is for, and what you are hoping it will do. We will review your lot against current Massachusetts ADU rules and your town's zoning, and we will walk you through what is actually possible.