The combination of the Bay Area being home to some of the leading prefab ADU builders in the country and high housing prices make building an ADU in the Bay Area a good decision. ADUs can increase a home’s livable square footage or produce extra rental income. But while the idea of building an ADU in the Bay Area might seem like a straightforward decision, executing the project might be slightly more difficult.

While changes are being made both at the local and state levels to simplify the ADU building process, there are still questions of “where can I find prefab ADUs in the Bay Area” and “who are the best ADU builders in the Bay Area”?

To help you navigate one of the first big decisions in the process, choosing a home and builder, we have created a list of the 8 best prefab ADUs for sale in San Francisco and the Bay Area. The ADUs on our list have been chosen due to their unique designs, construction type (modular, panelized kits, manufactured), and companies’ backgrounds as reputable ADU builders.

Best Prefab ADUs in the Bay Area

Origin by Blu Homes - Vallejo, CA

The Origin is the larger of two prefabricated ADUs from Blu Homes. It has two bedrooms and two bathrooms, one of which is part of the master suite, and a combined 1,000 square feet of living space. It features a modern exterior and open interior layout. The Origin’s base cost starts at $430,000 and will increase depending on the amount of site work necessary and any desired upgrades for the ADU.

As a company, Blu Homes is based in Vallejo, California, and exclusively works on projects in California. In addition to the Origin, they build one other, smaller ADU, and two single-family home designs though, models can be combined to create a larger, more customized home. While Blu Homes designs and manufactures home modules, a local builder is required to complete site preparations and finish the final stitch & seam. Our turn-Key cost estimate for an ADU or prefab home from Blu Homes ranges from $400 - $830 per square foot. For more info, see our list of Blu Homes ADUs with cost info.

700 by Digz2Go - Alameda, CA

The 700 is one of several pre-designed ADUs by Digz2Go. It features, one bedroom, one bathroom, and 700 square feet of living space. While it has been designed with a modern aesthetic, buyers are able to personalize their ADU so that it blends in with their primary residence. Base costs for the 700 start at $350,000.

Digz2Go is a custom design and architecture firm that specializes in prefab single-family homes and ADUs. While they are based in the Bay Area, they are able to take on projects across the country. Traditionally, they specialize in modern ADUs and homes. While they do offer site-visits and construction supervisory services, a local builder is required to complete all on-site construction. Our turn-Key cost estimate for an ADU or prefab home from Digz2Go ranges from $500 - $700 per square foot. For more info, see our list of Digz2Go ADUs with cost info.

Abodu Two by Abodu - San Jose, CA

The Abodu Two is the largest ADU model offered by Abodu. It offers 610 square feet of interior space and has two bedrooms and one bathroom. It features a modern exterior and interior, cathedral ceilings, and full size appliances. While the base price for the Abodu Two starts around $315,000, turn-key costs are likely to be closer to $350,000.

As a company, Abodu exclusively focuses on designing and building ADUs. They offer 3 styles of modern, cabin-like ADUs that range in size from 335 to 610 square feet. Buyers are able to personalize certain exterior & interior finishes. For projects in the Bay area, they offer turn-key project management services. Our turn-key cost estimate for an ADU or prefab home from Abodu ranges from $418 - $600 per square foot. Alternatively, see our list of Abodu ADUs with cost info.

Solo 3 by Bay Modular - Oakland, CA

The Solo 3 is one of four ADUs built and sold by Bay Modular. It has one bedroom, one bathroom, 480 square feet of interior living space, and a 96 square foot exterior patio. Like other Bay Modular models, it features a modern exterior and refined interior, all constructed from recycled shipping containers. Base prices for the Solo 3 ADU built by Bay Modular start at $273,000, though final costs with site work and permits are likely to be closer to $350,000.

Bay modular specializes in the design and construction of ADUs. While they do not work on fully-custom designs, buyers are able to personalize certain exteriors and interiors. They act as a turn-key builder, although some sub-trades are contracted out. What that means though, is that you will have one point of contact for the duration of your ADU build. Our turn-Key cost estimate for an ADU or prefab home from Bay Modular ranges from $400 - $800 per square foot. For more info, see our list of Bay Modular ADUs with cost info.

M650 by Villa Homes (San Francisco, CA)

Villa Homes’ M650 is one of 15 pre-designed prefab ADUs for sale in the Bay Area. It has two bedrooms, one bathroom, and 650 square feet of living space. Like all other ADUs from Villa Homes, the M650 includes high-end finishes like designer fixtures and faucets, a solar package, 10’ sliding glass doors, and stainless steel appliances. While the model cost for the M650 starts at $209,000, a turn-key project in the Bay Area is likely to have a starting cost of around $400,000.

Villa Homes (formerly Habitat Homes) is based in San Francisco and offers turn-key builder services for ADUs in the Bay Area. As a Bay Area ADU builder, they focus exclusively on ADUs and have models that range from 384 sqft studios to 1,200 sqft multi-bedroom ADUs. They offer turn-key project services and handle both the sales and construction of their modular ADUs as well as site work. They are transparent on their home costs, with starting costs typically for an ADU from Villa Homes in the Bay area costing between $322 - $920 per square foot. Or, see our full list of Villa Homes ADUs with cost info.

hybridcore homes prefab ADU builder — 2071 by hybridCore Homes

2071 by hybridCore Homes - Santa Rosa, CA

The 2071 by hybridCore Homes is a mid-size accessory dwelling unit. It features one bedroom and one bathroom with a combined 623 square feet of living space. hybridCore Homes is able to modify the exterior to meet customer wants, though possible styles include craftsman, farmhouse, cottage, Spanish, ranch, and modern farmhouse. Our cost estimate for the 2071 starts at $250,000.

HybridCore Homes focus on building prefab homes in the San Francisco Bay Area. They work with local construction sub-contractors to be able to offer turn-key project services in the northern Bay area. In addition to their prefab ADUs, they also build single family homes that can be as big as 5,500 square feet. Our turn-key cost estimate for an ADU or prefab home from hybridCore Homes ranges from $350 - $600 per square foot.

Avava Dwellings ADU — 264 by AVAVA Dwellings

Model 264 by AVAVA Dwellings - Berkeley, CA

Model 264 by AVAVA Dwellings is one of 5 pre-engineered, panelized ADUs for sale in the Bay Area. It is a 264 square foot studio with a bathroom and kitchenette. The ADU features a modern design and a range of personalization options for exterior and interior finishes. It is important to note that AVAVA Dwellings is a B2B company and only designs and manufactures the SIPs for local builders. As such, a local builder is your best point of contact for determining exact project pricing. It is our estimate however, that the Model 264 ADU has a starting cost of around $133,000.

AVAVA is a prefab ADU builder based in Berkeley, CA. What makes them unique to other prefab ADU builders is that they use a panelized build system. While this means that more on-site work may be necessary to assemble the panels and finish the home, it often addresses the common issue of poor site access. Our turn-Key cost estimate for an ADU from AVAVA Dwellings ranges from $400 - $600 per square foot. For more info, see our list of AVAVA Dwellings ADUs with cost info.

Shilo Prefab ADU in the Bay Area — Custom ADU by Shilo

Custom ADU by Shilo - San Francisco, CA

Shilo designs and builds fully custom ADUs in the Bay Area. Whereas other prefab companies offer a set of pre-designed models that, in some cases, can be modified or customized, Shilo has an in-house design team that works with buyers to create a one-of-a-kind design. That allows individuals to get exactly the ADU they want which can even be designed to match their primary residence.

As a company, Shilo acts as a full-service project manager and manages all phases of the build process. Our turn-Key cost estimate for a custom ADU from Shilo ranges from $325 - $455 per square foot. Due to the custom nature of their work, however, it is possible that your project cost exceeds this estimate. This is due to the large variance in finish costs and the range in site work costs.

ADU Builders in the Bay Area

Finding the right prefab ADU in the Bay Area is an important part in determining the specifics of your project. Another important factor to consider when choosing the best Bay Area ADU builder for your situation is builder-specific factors like cost, whether they offer custom work, and what their scope of services are. To help you compare those metrics, we have created a table that allows you to compare, side-by-side, the builders listed above.

It is also important to know that with prefab construction, you are not limited to companies that are based in San Francisco, Oakland, Marin, San Jose, etc. With prefab construction entire ADUs can be manufactured off-site and shipped to your lot. Or, the structural panels can be manufactured, flat packed, shipped, and assembled on site. This means that you can work with companies as far away as Los Angeles, Seattle, Denver, or even New York.

In those cases the cost of shipping and the cost and availability of local labor may determine whether that is a wise decision for your project. When shipping an ADU, you should estimate shipping costs of up to $15 per mile. And when working with a non-local company, you will likely need to find and manage a company or several sub-contractors to prepare your building site, install the module, and complete any necessary finishes.

	Blu Homes (Vallejo)	Digz2Go (Alameda)	Abodu (San Jose)	Bay Modular (Oakland)	Villa Homes (San Francisco)	hybridCore Homes (Santa Rosa)	AVAVA Dwellings (Berkeley)	Shilo (San Francisco)
Cost (per sqft)	$400 - $830	$500 - $700	$418 - $600	$400 - $800	$322 - $920	$350 - $600	$400 - $600	$325 - $455
Custom	No	Yes	No	No	No	No	Yes	Yes
Turn-Key Builder	No	No	Yes	Yes	Yes	Yes	No	Yes

If you would like to consider ADU builders that are based outside of the Bay Area but can still ship their products to Northern California, some companies to look into include:

Other resources to help you find and build the best prefab ADU in the Bay Area or select an ADU builder in San Francisco include: