ADU Construction & In-Law Suite Services in Maine, Massachusetts & New Hampshire

3D Rendering of Bright, modern interior with a kitchen, dining area, and living room; light wood floors and white walls.
3D rendering of Bright, open-concept living space with a dining area, kitchen, and seating area under a sloped ceiling.

Expand Your Home with Flexible ADU Housing & In-Law Suites

Looking for more space? Whether you’re hoping to accommodate family, earn rental income, or simply add flexibility to your property our ADU construction services deliver professionally built, code-compliant additional dwelling units (ADUs), in-law suites, and secondary residences.


From detached backyard cottages to attached additions and garage conversions, we create ADU housing that fits your needs, increases your home’s value, and adapts to changing lifestyles.

Schedule Your FREE Discovery Call

What is an ADU / In-Law Suite / Additional Dwelling Unit?

An ADU (also often called an in-law suite, additional dwelling unit, or secondary unit) is a smaller, independent living unit located on the same lot as a single-family home. 


ADUs can take several forms:


Detached units

a separate structure on your property (e.g. a backyard cottage or converted garage).


Attached units / Additions

an added wing or expanded portion of your existing home.


Interior conversions

converting existing space (e.g. basement, attic, or unused rooms) into a self-contained living unit.



Each ADU is designed to include independent living amenities  bedroom, kitchen (or kitchenette), bathroom, and separate entrance ensuring privacy and functionality regardless of how it’s built.

Our ADU Construction & In-Law Suite Process

Every ADU project is unique, and we tailor our approach to fit the specific needs, goals, and layout of your property. Unlike contractors who rely on a one-size-fits-all model, we take a personalized, hands-on approach from the very first conversation through final completion.

Telephone handset icon.

Discovery Call/Visit

We begin with a detailed discovery call to understand your goals for the ADU or in-law suite, your budget expectations, preferred timeline, and how you envision the new space being used. We also walk you through our process so you know exactly what to expect at each step.

Clipboard with house icon and hard hat.

Initial Site Visit

Next, we conduct an on-site walkthrough of your property to get a clear understanding of the layout, access points, utilities, grade, and overall feasibility. This visit helps us determine the best ADU placement and structure type—detached, attached, or interior conversion.

Engineer with helmet holding blueprints, surrounded by tools and a globe.

Architectural Design

We collaborate with professional architects to develop detailed plans for your ADU. Depending on the complexity of the design, the architect may require an additional site visit to take precise measurements or evaluate structural considerations. This phase ensures your ADU is thoughtfully designed, code-compliant, and fully aligned with your goals.

Two wrenches, one standard and one adjustable, for mechanical work.

Estimating Phase

Once the architectural plans are complete, we prepare a detailed estimate for the framing and demolition (if required). At the same time, we coordinate with our licensed trade partners—plumbing, electrical, HVAC, and others to assemble the supplemental pricing needed for a full project scope. This gives you a transparent, all-inclusive understanding of your investment.

Document with shop icon being stamped.

Permits & Utility Coordination

We handle all necessary building permits and assist with utility company sign-offs, ensuring your project meets all local building, zoning, and safety requirements. Our team takes care of the paperwork and communication so you can focus on planning your new space.

Construction worker wearing a hard hat, beard, and safety vest.

Full Construction Management

Once approved, we manage the entire ADU construction process from start to finish. This includes site preparation, foundation work, framing, utilities, interior finishes, inspections, and final walkthrough. Our team ensures every phase is executed with precision, quality craftsmanship, and clear communication.

Telephone handset icon.

Discovery Call/Visit

We begin with a detailed discovery call to understand your goals for the ADU or in-law suite, your budget expectations, preferred timeline, and how you envision the new space being used. We also walk you through our process so you know exactly what to expect at each step.

Engineer with helmet holding blueprints, surrounded by tools and a globe.

Architectural Design

We collaborate with professional architects to develop detailed plans for your ADU. Depending on the complexity of the design, the architect may require an additional site visit to take precise measurements or evaluate structural considerations. This phase ensures your ADU is thoughtfully designed, code-compliant, and fully aligned with your goals.

Document with shop icon being stamped.

Permits & Utility Coordination

We handle all necessary building permits and assist with utility company sign-offs, ensuring your project meets all local building, zoning, and safety requirements. Our team takes care of the paperwork and communication so you can focus on planning your new space.

Clipboard with house icon and hard hat.

Initial Site Visit

Next, we conduct an on-site walkthrough of your property to get a clear understanding of the layout, access points, utilities, grade, and overall feasibility. This visit helps us determine the best ADU placement and structure type—detached, attached, or interior conversion.

Two wrenches, one standard and one adjustable, for mechanical work.

Estimating Phase

Once the architectural plans are complete, we prepare a detailed estimate for the framing and demolition (if required). At the same time, we coordinate with our licensed trade partners—plumbing, electrical, HVAC, and others to assemble the supplemental pricing needed for a full project scope. This gives you a transparent, all-inclusive understanding of your investment.

Construction worker wearing a hard hat, beard, and safety vest.

Full Construction Management

Once approved, we manage the entire ADU construction process from start to finish. This includes site preparation, foundation work, framing, utilities, interior finishes, inspections, and final walkthrough. Our team ensures every phase is executed with precision, quality craftsmanship, and clear communication.

Telephone handset icon.

Discovery Call/Visit

We begin with a detailed discovery call to understand your goals for the ADU or in-law suite, your budget expectations, preferred timeline, and how you envision the new space being used. We also walk you through our process so you know exactly what to expect at each step.

Engineer with helmet holding blueprints, surrounded by tools and a globe.

Architectural Design

We collaborate with professional architects to develop detailed plans for your ADU. Depending on the complexity of the design, the architect may require an additional site visit to take precise measurements or evaluate structural considerations. This phase ensures your ADU is thoughtfully designed, code-compliant, and fully aligned with your goals.

Document with shop icon being stamped.

Permits & Utility Coordination

We handle all necessary building permits and assist with utility company sign-offs, ensuring your project meets all local building, zoning, and safety requirements. Our team takes care of the paperwork and communication so you can focus on planning your new space.

Clipboard with house icon and hard hat.

Initial Site Visit

Next, we conduct an on-site walkthrough of your property to get a clear understanding of the layout, access points, utilities, grade, and overall feasibility. This visit helps us determine the best ADU placement and structure type—detached, attached, or interior conversion.

Two wrenches, one standard and one adjustable, for mechanical work.

Estimating Phase

Once the architectural plans are complete, we prepare a detailed estimate for the framing and demolition (if required). At the same time, we coordinate with our licensed trade partners—plumbing, electrical, HVAC, and others to assemble the supplemental pricing needed for a full project scope. This gives you a transparent, all-inclusive understanding of your investment.

Construction worker wearing a hard hat, beard, and safety vest.

Full Construction Management

Once approved, we manage the entire ADU construction process from start to finish. This includes site preparation, foundation work, framing, utilities, interior finishes, inspections, and final walkthrough. Our team ensures every phase is executed with precision, quality craftsmanship, and clear communication.

Why Choose Sensible Home Solutions for Your ADU / In-Law Suite Build

As a veteran-owned, family-run contractor, we combine integrity, craftsmanship, and service to ensure every homeowner receives the highest level of care. Homeowners choose us because we offer:


Complete ADU Construction Expertise

We specialize in building detached ADUs, attached additions, and interior conversions tailoring to your property and family needs.


Veteran-Owned Professionalism

We operate with integrity, accountability, and a commitment to serving our customers and community.


Custom Design Options

From tiny in-law suites to full secondary homes — we design to your vision, budget, and use (rental income, guest house, family suite).


Maximize Property Value & Usage

Adding an ADU can increase your property’s utility, versatility, and value  whether for family, rental, or future resale.




Frequently Asked Questions About ADU Construction & In-Law Suites

  • What’s the difference between an “ADU,” “in-law suite,” and “additional dwelling unit”?

    They’re all terms for the same concept — a self-contained living unit on single-family property. “ADU” (Accessory Dwelling Unit) is the formal term; “in-law suite,” “additional dwelling unit,” or “secondary unit” are common synonyms.

  • Can an ADU be detached or attached?

     ADUs can be detached standalone units (like a cottage, guest house, or converted garage) as well as attached additions to the existing home; or built by converting existing interior space (like a basement or attic).

  • Does an ADU need its own kitchen, bathroom, and entrance?

    Yes to qualify as an ADU it must be a fully functional, independent living unit with sleeping, cooking, bathing, and a separate entrance for privacy.

  • Why build an ADU / in-law suite on my property?

    ADUs give you flexibility: host family members, generate rental income, provide extra privacy, or add value to your home all without buying new land.

  • How much does an ADU cost?

    ADU's vary greatly in there size, type, and design. Unfortunately we cannot accurately provide a ball park price range for these projects. 

  • What is the cost to get a quote for the estimate?

    We perform a free discovery call and initial visit. If you would like to move forward with the design phase, there is a fee for the Architech, cost depends on project scope.

  • I have a septic tank, can I still build an ADU?

    Yes, but we will need to get your septic systerm evaluated. The min requirment for most municipalities is to have a septic shelf plan on file which is a plan to install a new septic system.

Ready to Add an ADU? Schedule Your Free Discovery Call

If you’re thinking about adding an in-law suite, guest home, or secondary unit now is a great time. Contact us for a free consultation. We’ll walk you through your options, design a solution to meet your needs, and deliver an ADU built to last.

Schedule Your Free Discovery Call Today

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