Pro's Edge Small Homes is a licensed ADU contractor in MA & NH with 20+ years experience. They offer turnkey design, permitting & modular construction of granny flats, in-law suites & backyard cottages, including a free property evalua... 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
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
Millbrook Construction Corp. in Boston specializes in ADU construction, handling design, permits, and builds. Services include detached ADUs, garage conversions, and in-law suites for rental income, family housing, or added property value.
read more
Design 1 Kitchen & Bath designs and builds ADUs in Massachusetts, handling consultation, design, permitting, and construction. ADUs add rental income, multigenerational living space, and property value for Greater Boston homeowners.
read more
G.M. Roth Design Remodeling offers full-service ADU construction in southern NH and northeastern MA. With 40+ years of experience, they handle zoning, design, permitting, and build. CAPS-certified, serving Nashua, Manchester, Chelmsford & more... read more
BlackDog Builders offers full-service ADU design/build solutions, handling design, permitting, and construction under one roof. Specializing in detached ADUs, backyard cottages, in-law suites, and granny flats, they back projects with a 3-year war... read more
Trust Contractors designs and builds ADUs, including detached units, garage conversions, basement ADUs, and in-law suites. Services cover zoning, permits, and construction, helping homeowners add rental income, family housing, or flexible living s... read more
River City Construction is a Boston-based ADU contractor specializing in home additions, garage conversions, in-law suites & detached backyard cottages. They manage design, permitting & full construction under one roof.
read more
FiveTen Construction & Design is a Massachusetts ADU contractor offering design, permitting, and construction services. They build detached, attached, basement, and garage ADUs, ensuring full compliance with MA building codes and zoning regula... read more
Alcantara Construction is an experienced ADU contractor specializing in detached ADUs, garage conversions, JADUs, in-law suites, and granny flats. They guide homeowners through planning, permitting, and building accessory dwelling units efficientl... 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
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 homeo... read more
T&J Builders specializes in custom ADUs in Dover NH, Portsmouth NH, NH Seacoast, Lakes Region & Southern Maine. Services include garage conversions, in-law suites & detached cottages for rental income, multigenerational living & ad... 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 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.