Last updated: September 24, 2026
What affects the price
Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.
About this service
A detached ADU is a standalone building separate from your main home, like a backyard cottage. These provide the most privacy for you or your tenants since there are no shared walls. You need this if you have a large enough yard to accommodate a separate structure.
Frequently asked in Berkeley
What is the cost to build an accessory dwelling unit in Berkeley?
What kind of ADU company serves Berkeley?
What do accessory dwelling unit homes look like?
Can I add a backyard accessory dwelling unit in Berkeley?
What is the accessory dwelling unit construction cost in Berkeley?
What is the best accessory dwelling unit for my property?
Are 24-hour ADUs available?
Also serving nearby: Richmond · Oakland · Daly City · Vallejo · Concord
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Berkeley — population 118,962; about 11,403 residents per square mile across 10.4 sq mi. ZIP codes covered include 94701, 94702, 94703, 94704, 94705, 94707, 94708, 94709.
Neighborhoods served in Berkeley: Gourmet Ghetto, South Berkeley, North Berkeley, West Berkeley, Claremont — and every surrounding area.
Areas we serve
Browse by state, then city.
