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
An ADU unit is simply a secondary dwelling located on the same lot as a primary residence. You might look into an ADU if you need more space for a home office, a gym, or housing for extended family. Exact pricing confirmed free on the call.
Frequently asked in Portsmouth
What are modular accessory dwelling units in Portsmouth?
Are there accessory dwelling unit rules in New Hampshire that apply to Portsmouth?
What's the ADU permit process in Portsmouth?
How do I find accessory dwelling unit services near me in Portsmouth?
What is ADU housing in Portsmouth?
What is accessory dwelling unit rental in Portsmouth?
Where can I find ADU near me 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: Historic Downtown, The South End, The North End, Pease International Tradeport, Olde Port — and every surrounding area.
Areas we serve
Browse by state, then city.
