Mass ADU is a Massachusetts-based ADU contractor offering full-service accessory dwelling unit construction. Services include free consultations, permitting, design, and build. They serve homeowners statewide with a clear 3-step process.
read more
Planning an ADU in Massachusetts? Costs range from $250–$500+ per sq ft. State law now allows ADUs by right on single-family lots. Learn about permits, the Stretch Energy Code, and working with a qualified ADU contractor in Greater Boston.
read more
ADUs are now legal statewide in Massachusetts. Atlantic Property Development builds custom Accessory Dwelling Units on the North Shore, offering design, permitting, and construction services for detached, attached, and garage conversion ADUs.
read more
Guiding Builders specializes in ADU construction, offering design, permitting, and building services. Projects include detached ADUs, garage conversions, in-law suites, granny flats, and casitas—custom-built to add value and living space.
read more
Honorato Company offers a structured construction process in Boston, covering ADUs, garage conversions & renovations. From consultation to final walkthrough, they ensure transparency, permitting, design, and clear communication throughout.
read more
Post Woodworking builds custom Accessory Dwelling Units (ADUs), including detached ADUs and in-law suites. They offer flexible involvement, from full construction management to building only, ensuring seamless integration with your existing home.
read more
At Hobart Contracting, we design and build high-quality Accessory Dwelling Units (ADUs) that fit your lifestyle and property. Whether you’re planning a guest house, in-law suite, rental unit, or private retreat, our team creates spaces that are functional, beautiful, and built to last.
read more
Sensible Home Solutions builds ADUs, in-law suites & secondary living spaces across Maine, Massachusetts & New Hampshire. Services include detached units, garage conversions & basement ADUs. Free discovery call available.
read more
New England Additions, backed by Sordan Construction, offers pre-designed ADU builds across 25+ Greater Boston communities. Specializing in in-law suites and detached ADUs, they streamline permitting, budgets, and timelines for Massachusetts homeowners.
read more
ADU 4 You is a Boston-area ADU contractor offering full-service design, permitting, and construction of accessory dwelling units, including detached ADUs, in-law suites, and garage conversions, with fixed-price quotes and ROI estimates.
read more
Kinstruct Tiny Homes is a Pacific Northwest contractor specializing in tiny homes and ADUs, including detached ADUs, backyard cottages, granny flats, and in-law suites built to maximize space and meet local codes.
read more
North Shore ADU Home Builders LLC builds custom ADUs up to 900 sq ft across Massachusetts. Services cover design, permits & construction. Rental income ranges $1,800–$3,500/month. Property values may rise $100K–$250K.
read more
Massachusetts ADUs are now legal by right statewide after 2024 legislation. MBA Builders offers full-service ADU construction across Greater Boston, with structured preconstruction planning and builds starting around $450/sq ft.
read more
Walczak Design and Build LLC is a trusted ADU contractor on Massachusetts' North Shore, serving Ipswich, Newburyport, Beverly & more. They offer full-service ADU design, permitting, and construction with transparent planning and expert project management.
read more
Top-Pro Construction, Inc. is Greater Boston's trusted ADU builder with 25 years of experience. Specializing in detached ADUs, attached units, garage conversions & basement ADUs to boost property value and rental income.
read morePortsmouth, New Hampshire is one of the oldest cities in the United States, founded in 1623 along the Piscataqua River. This rich history means that many neighborhoods feature historic homes and protected districts, which creates unique challenges for ADU contractors working in the area. If you are considering adding an Accessory Dwelling Unit to your Portsmouth property, working with experienced local ADU contractors who understand the city's specific zoning codes, historic preservation guidelines, and building regulations is absolutely essential.
Portsmouth has made efforts to encourage ADU development as part of addressing the region's housing needs. Under Portsmouth's zoning ordinance, ADUs are permitted in most residential zones, including single-family and multi-family districts. However, there are important rules that your ADU contractor must navigate carefully:
A significant portion of Portsmouth's residential properties fall within or near designated historic districts, such as the Strawbery Banke neighborhood. ADU contractors working in these areas must obtain a Certificate of Approval from the Historic District Commission before construction can begin. This means that exterior materials, window styles, rooflines, and overall design must be compatible with the historic character of the surrounding neighborhood. Skilled ADU contractors in Portsmouth are familiar with these requirements and can help homeowners design units that satisfy both modern functionality and historic preservation standards.
Hiring a contractor with direct experience in Portsmouth is a significant advantage. Local ADU contractors understand the nuances of working with the Portsmouth Planning Department, the Building Division, and the Historic District Commission. They are also familiar with the city's infrastructure, including older utility connections and foundation types common in New England homes, which can affect ADU construction costs and timelines.
Whether you are planning a garage conversion, basement ADU, or a new detached backyard cottage, working with qualified ADU contractors in Portsmouth, NH ensures your project meets all local codes and historic guidelines while maximizing your investment.