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
A modular unit is built in a factory and then transported to your property to be finished on a foundation. You should consider this if you want a faster construction timeline with less disruption to your daily life. It is an efficient way to add high-quality space to your lot.
Frequently asked in Portsmouth
What's involved in ADU building in Portsmouth?
What ADU services are available in Portsmouth, VA?
Who is an accessory dwelling unit contractor in San Diego County near Portsmouth?
What's the best ADU for my home in Portsmouth?
What is ADU housing in Portsmouth?
Can I have homes with in-law suites in Portsmouth?
What is a backyard 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, Churchland, Waterview, Highland — and every surrounding area.
Areas we serve
Browse by state, then city.
