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
Frequently asked in Portsmouth
Who are the best ADU builders for projects in Portsmouth?
What is the cost to build an accessory dwelling unit in Portsmouth?
What are the advantages of a detached accessory dwelling unit in Portsmouth?
Can I find an affordable ADU in Portsmouth?
What ADU services are available for residents in Portsmouth?
What is involved in getting an ADU quote in Portsmouth?
What is the cost of an accessory dwelling unit 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, Cradock, Waterview, Churchland, Olive Branch — and every surrounding area.
Areas we serve
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