Prefabricated accessory dwelling unit

Looking for prefabricated accessory dwelling unit in San Francisco, CA? Call AccessoryDwellingUnit Experts for a contact a provider — no obligation. Licensed adu builders serve San Francisco and the surrounding area, and you'll get straight answers on timing and what affects the price.

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 prefab ADU is built in a factory and then transported to your property for final assembly. These units are often faster to build than traditional construction because the work happens in a controlled environment. If you want to minimize noise and debris on your property or need a quicker turnaround for your backyard space, this is a great option.

Frequently asked in San Francisco

How can I build an affordable accessory dwelling unit in San Francisco?

What are the requirements for an ADU permit in San Francisco?

How does accessory dwelling unit construction work in San Francisco?

What is the best way to find ADU builders in San Francisco?

What does 'accessory dwelling unit' mean in San Francisco?

In San Francisco, an accessory dwelling unit (ADU) is a secondary housing unit on a single-family lot. It can be attached to the main home, like an in-law unit, or detached, such as a backyard cottage. ADUs must provide independent living facilities. The city has specific regulations governing their size and placement. We ensure the pros you speak with know these rules.

Are there emergency ADU services available in San Francisco?

What are the advantages of accessory dwelling unit homes?

Accessory dwelling unit homes offer numerous advantages. They provide extra rental income potential, multigenerational living options, and increased property value. For homeowners, they can offer a space for aging parents or adult children. They also add density to the housing stock without requiring large new developments. We help you explore these benefits through expert advice.

Also serving nearby: Daly City · Richmond · San Mateo · Berkeley · Oakland

All cities in California →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

808,988residents

17,323per sq mile

8ZIP codes served

Serving all of San Francisco — population 808,988; about 17,323 residents per square mile across 46.7 sq mi. ZIP codes covered include 94102, 94103, 94104, 94105, 94107, 94108, 94109, 94110.

Neighborhoods served in San Francisco: The Mission District, Hayes Valley, Noe Valley, The Sunset District, Richmond District, Daly City — and every surrounding area.