Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.
About this service
Building an accessory dwelling unit in Massachusetts means navigating specific state-level zoning laws and local town requirements. You need this service if you own property in the state and want to add a secondary unit for aging parents, adult children, or rental income. We understand the local regulatory landscape to help you avoid common pitfalls.
Frequently asked in Portsmouth
What is a backyard accessory dwelling unit in Portsmouth?
What are accessory dwelling unit services in Portsmouth?
What are accessory dwelling unit companies?
Where can I find an ADU near me in Portsmouth?
What is a 24-hour ADU service?
What is an accessory dwelling unit for rent?
Are there accessory dwelling unit grants available in Portsmouth?
Also serving nearby: Norfolk · Chesapeake · Hampton · Newport News · Virginia Beach
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Portsmouth — population 96,793; about 2,906 residents per square mile across 33.3 sq mi. ZIP codes covered include 23701, 23702, 23703, 23704, 23705, 23707, 23708, 23709.
Neighborhoods served in Portsmouth: Olde Towne, Ghent, Downtown Portsmouth, Churchland, Cradock — and every surrounding area.
Areas we serve
Browse by state, then city.
