ADU Construction & In-Law Suite Services in Maine, Massachusetts & New Hampshire
Accessory dwelling units — commonly referred to as ADUs, in-law suites, or secondary living spaces — give homeowners flexible options for accommodating family, guests, or generating rental income, all while remaining on the same property. Sensible Home Solutions works with homeowners across New England, helping plan, design, and construct ADUs that meet local requirements, integrate with existing homes, and function well for everyday use.
An ADU is a self-contained living space built on the same property as an existing home. It typically includes a sleeping area, bathroom, and small kitchen. Depending on the property and the homeowner's needs, it can be attached to the main house, built as a standalone structure, or created by converting existing space. The right approach depends on zoning rules, lot layout, utilities, privacy needs, and how the space will ultimately be used — whether for aging parents, family members, or supplemental rental income.
Types of ADUs Sensible Home Solutions Builds
There is no single solution that works for every property. Sensible Home Solutions helps homeowners identify the right approach based on their specific situation. The types of ADUs they build include:
- Detached Backyard ADU — standalone cottage or small structure builds
- Attached ADU / In-Law Suite — connected to the main home with its own entrance
- Garage Conversion ADU — converting existing garage space into a livable unit
- Basement ADU — lower-level living spaces designed with proper egress and moisture control
Each ADU is designed to include independent living amenities — a bedroom, kitchen or kitchenette, bathroom, and a separate entrance — ensuring privacy and functionality regardless of the construction type.
Because ADUs function like small homes on the same property, they involve more complexity than a typical home improvement project. Sensible Home Solutions takes a planning-first approach before any building begins. Their process covers:
- Feasibility and Zoning Review — understanding setbacks, lot coverage, height restrictions, and local ADU regulations
- Design and Layout Planning — making the space functional, private, and comfortable
- Utility Planning — determining the best approach for water, electrical, sewer, and HVAC
- Structural and Site Considerations — foundations, drainage, grading, access paths, and tie-ins
- Permitting and Inspections — managing approvals so the project is built legally and correctly
Budgeting and Cost Considerations
One of the most important early conversations in any ADU project is establishing realistic budget expectations before design progresses too far. ADUs include many of the same components as a full home — foundation, framing, roofing, electrical, plumbing, and finishes — all within a smaller footprint.
Several factors influence overall cost:
- Size, design complexity, and site conditions all affect pricing
- Detached units typically cost more than interior conversions due to additional foundation and utility work
- Conversions may appear simpler, but code compliance upgrades and safety requirements can affect the final cost
Sensible Home Solutions walks homeowners through budget expectations early in the process, so design decisions align with what makes financial sense before any major commitments are made. ADU costs vary considerably based on type and scope, and an accurate estimate requires a proper evaluation of the project.
Initial consultations begin with a free discovery call and site visit. If a homeowner chooses to move forward into the design phase, there is a fee for the architect, which depends on the scope of the project.
For homeowners with a septic system, an ADU can still be built, but the septic system will need to be evaluated. Most municipalities require a septic shelf plan on file — essentially a plan to install a new septic system if needed.
Sensible Home Solutions serves homeowners across Maine, Massachusetts, and New Hampshire. Whether someone is exploring an in-law suite, a detached backyard cottage, or a garage conversion, they offer an initial conversation to discuss feasibility, costs, and next steps before any commitments are made.