11 Best Prefab ADUs in California and Factors to Consider

May 23, 2022

So you’re ready to add an accessory dwelling unit (ADU) to your California property, whether to add value to your current property, make passive income renting it out, or house older family members. Maybe the thought of disrupting your backyard for several months keeps you from moving forward with an ADU project. Fortunately, you have the option of ordering a ready-to-go ADU that skips the backyard mess, instead delivering a pre-built home to your property.

A prefabricated (prefab) ADU is built offsite at a manufacturer and brought to your site once it’s ready for installation. Building this type of unit is typically faster than constructing an ADU from the ground up on your property. It can help control the costs as well, as prefab ADUs are built based on already-made plans that skip the architecture and design process.

If you’re ready to add an ADU to your property but the hassle keeps you from doing so, a prefab home is the way to go. You’ll need to start by finding a company that can execute your ideas and deliver a quality build. In this article, you’ll learn about the best prefab ADU California companies and the services and features they offer.

What to consider when choosing a prefab ADU

When choosing a prefab ADU, there are some factors you should consider to ensure your choice meets your expectations. Below, you’ll find a few points you’ll want to check off your list as you’re deciding on a prefab ADU.

1. Size of the unit

You should go in knowing how large (or small) you want your ADU to be. This way, you can ensure that your ADU home builder company offers that sizing option. 

In California, the average size of an ADU is 615 square feet. Most ADUs fall in the range of 300 to 1,400 square feet. Spacial’s studio ADUs are 400 square feet, and Spacial’s one-bedroom ADUs are 500 square feet. The point is: You have some flexibility in determining the size of your ADU.

Notably, each jurisdiction in California can set its own maximum size limits. For example, in San Francisco, one-bedroom ADUs can be up to 800 square feet. The state maximum of 1,200 square feet remains in place no matter your ADU’s number of rooms. 

Photo of design plan
Photo by Scott Blake on Unsplash

2. ADU design and floor plan

Though ADUs are smaller versions of traditional homes, they don’t have to feel cramped or cluttered. As you’re researching prefab ADU companies, look through their layouts and design options. With the right design scheme, your unit can feel spacious and airy. To make your ADU this welcoming, opt for layouts that make the most of your unit’s space. 

You’ll fare best with an open floor plan. Fewer partition walls between kitchen, living, and dining areas can create larger spaces with better flow. Try to bring in natural light wherever possible, as this feature will also make your unit appear bigger. Opt for large windows, a skylight, and sliding glass doors. You might also choose whole-wall doors made of glass that bring even more light into your unit and create a seamless indoor-outdoor living space.

ADU designs with tall ceilings and open wall space for storage can also increase your unit’s spacious feel. (However, many California jurisdictions enforce an ADU height limit of 16 feet.) Further, dark-colored paint doesn’t reflect light, so it can make a space feel artificially small. Instead, choose a light color that complements the natural light entering your unit.

The best ADU designs incorporate plenty of built-in storage space. This way, you don’t have large dressers taking up floor space. You might decide to use wall storage, shelves, and multifunctional furniture to keep your floor plan as open as possible. 

3. Planning and design team

As you research ADU companies, check to see whether they’ll handle the planning process. Some companies have in-house teams dedicated to the planning and design phases, while others contract with outside teams to complete these processes.

Either way, you’ll want to make sure these teams include reputable architects and building experts. This way, you can be confident that your ADU will meet the required standards and stand the test of time. Once you’ve selected a company, they should remain in regular contact to show you that they’re accurately capturing and executing your ideas.

Team conversation with client
Photo by Headway on Unsplash

4. Certifications

ADUs can be an environmentally sustainable living option. Their energy footprint is often much lower than that of traditional houses. If you want to ensure your ADU is built for low environmental impact – especially in a place like California, where certain energy efficiency standards are required – you’ll need a company that meets California’s Title 24 standards.

The Certified Passive House Designer certificate is another building standard that assesses homes based on their ecological footprint. Companies that can achieve this certification have the knowledge and experience needed to build energy-efficient, comfortable homes.

Your ADU company should also follow the California Green Building Standards Code, also known as CALGreen. These mandatory regulations include standards for environmental factors such as energy and water efficiency and material conservation. All Spacial ADUs meet CALGreen and most Passive House certification requirements.

5. Turnkey service capabilities

How long after delivering your ADU will it be ready for move-in? A turnkey ADU services provider will ensure your ADU is ready to go the moment the installation crew leaves your property. The company will handle the entire process of adding an ADU to your property. That means designing permit sets, obtaining permits, connecting the water and electrical systems, installing the unit, and everything in between.

When you work with Spacial, we’ll take care of building and delivering your ADU from start to finish. Your ADU will be ready with all the fixtures and appliances it needs to welcome you, your guests, or your tenants to a new home.

11 best prefab ADUs in California

Several companies in California specialize in building prefab ADUs. If you’re ready to start your ADU project, below are 11 of the best prefab ADU companies in the Golden State.

1. Plant Prefab

Plant Prefab focuses on designing and building custom full-sized family homes. You can either work with a Plant Prefab architect or hire an expert of your choice to execute your ideas. You can also select from one of Plant Prefab’s existing models and add your own customizations.

Plant Prefab’s process of building an ADU offsite is about twice as fast as building a unit from the ground up on your property. Its homes meet LEED Platinum standards, so Plant Prefab incorporates the essentials for energy efficiency and environmental responsibility. The company also focuses on maintaining sustainable processes, from sourcing materials to constructing units. As with many ADU manufacturers, Plant Prefab’s construction process produces less waste and uses fewer materials than traditional construction projects.

2. Spacial

A premium, seamless experience from planning to moving in: That’s what Spacial is all about. We offer volumetric modular studio and one-bedroom ADUs that maximize space with open floor plans and built-in storage for a spacious, free-flowing feel. Our units welcome plenty of natural light so the space is bright and airy. In collaboration with the world-renowned architecture firm CAZA, we take your ideas and turn them into stunning real-life manifestations of your vision. 

Living Room in Spacials One Bedroom ADU
Photo by Spacial

From the first day, we take care of the ADU permitting, planning, building, and installation processes behind the scenes. This way, you can focus on how you’ll take advantage of the many benefits an ADU can bring. We’ll handle all the heavy lifting, literally and figuratively – surveying your site, obtaining permits, laying the foundation, setting up utilities, and delivering and installing your unit. 

You’ll also have a dedicated Spacial consultant readily available to answer all your questions and guide you through the entire process. We want this process to be as straightforward for you as it is for us. 

We include only high-quality appliances and fixtures in our ADUs so you can enjoy the finest experience. Sustainability is at the core of all our operations and products too – our ADUs are the greenest around. Each of our units meets LEED requirements as well as most Passive House certification standards. Our ADUs also adhere to the CALGreen code, so you can be confident your new property has come together with careful environmental consideration.

3. Dvele

Dvele offers several options for modern customizable homes. One of this company’s specialties is smart technology. Many Dvele ADUs include automated software and sensors that collect real-time data to learn residents’ daily patterns and ways it can best serve their routines. Air conditioning, water heating, and humidity controls work to keep these homes energy-efficient.

Dvele offers floor plans, finishes, and additional features that come together in a custom lookbook based on your ideas. When you provide a few more details about your site and plans, you can also get an estimated cost for your project.

4. Shelter Dynamics

Shelter Dynamics offers two-bedroom and three-bedroom units called the Flex and Sage homes. The designs for these units include lots of unusual curves and rounded aspects. Vaulted ceilings and large windows maximize the space in these units.

Shelter Dynamics is also on board with producing sustainable and energy-efficient homes. The company designs its units to be Net Zero Ready, meaning they’re able to produce just as much (or more) energy as they consume. Energy Star appliances, a solar panel array, and a hybrid electric heat-pump water heater keep costs down while doing less harm to the environment.

5. Meka Modular

Meka Modular offers 13 home models of several sizes, including 160-square-foot one-bedroom units. Each model includes a detailed floor plan and a base price that includes the cost of interior finishes and shipping. This price can give you a rough idea of where to start your budget, though your cost may increase. 

If you don’t see what you’re looking for with one of Meka Modular’s pre-designed models, Meka also offers custom builds. Either way, all Meka Modular homes are built to meet three main criteria. First, each home follows a contemporary design with a spacious layout. Meka Modular’s homes also adhere to local building codes. Finally, the homes are constructed to withstand outdoor elements such as high winds and earthquakes.

6. Method Homes

Method Homes focuses on crafting sustainable, healthy homes. It typically builds full-sized homes rather than ADUs. You have the option to build a Net Zero Energy home with insulation, air, and solar energy systems that make your home more energy-efficient and cost-effective. Method Homes is also enrolled in certification programs, such as LEED and Passive House, to ensure its homes meet green environmental standards.

Method Homes follows a structured process that begins with a consultation so the planning team can learn about your vision, property, and budget. Along the way, Method Homes will gather the necessary permits, review your designs and aesthetic plans, and begin construction. Once the unit is complete, the company’s installation team can place the home on a property in one day. From there, the project’s general contractor will finish the installation process.

7. Connect Homes

With 15 models available, Connect Homes has options for building new homes and modern ADUs for less money than constructing traditional homes. Near the beginning of the planning process, you’ll receive an estimated budget. These costs may vary depending on several factors – the budget is always an estimate.

ADUs from Connect Homes are crafted to be airy and open. They also feature high-end fixtures and appliances. You can choose finishes, fixtures, and appliances to customize your home. Connect Homes will also submit your ADU permit set to city and county officials on your behalf. Once your home is delivered, a team will install the essentials to get it ready for move-in.

8. Maxable

Maxable is a marketplace created to help homeowners find the right turnkey ADU services provider for adding an ADU to their property. The company has experts ready to help define your plans for your unit’s design. When you’ve solidified your design, a reviewer will come to your property. This reviewer will evaluate your site’s readiness and ask you more questions about your project goals.

Once you’re ready to go, Maxable will guide you through meeting local standards, applying for permits, and hiring experienced teams to execute your ideas. You’ll also have access to Maxable’s platform where you can track invoices and see updated information about your project’s status.

9. Clever Homes

Clever Homes works from a set of templates and design systems to develop unique for sustainable ADU projects. ADUs from Clever Homes are LEED-certified and Net Zero Energy. Many of these homes have sustainable features such as water catchment, solar panels, and systems that run on alternative energy sources. There are also options for framing with steel and recycled materials instead of wood.

Clever Homes will guide you through the process of adding an ADU to your property. To start, you’ll receive an all-inclusive price estimate that accounts for the costs associated with your project. These costs include a fee that’s 12 percent of your total budget, and you can pay this fee in up to seven installments.

10. Villa Homes

Villa Homes offers 15 ADU models, including studio and one-bedroom designs. These homes come with standard features, including energy-efficient windows, can lights, a solar-ready roof, and an electric furnace.

The company’s instant quote tool can give you a pricing estimate based on the specific features, amenities, and upgrades you want in your ADU. From there, the design team will create a detailed proposal for your project. Villa Homes will oversee the permitting process and, once approved, start construction. After the company constructs your ADU off-site, it will deliver it to your home. Thereafter, getting it ready for move-in takes a month or two.

11. Abodu

Abodu’s backyard ADUs include options for standard or upgraded features and amenities. The company also offers pre-approved plans to expedite the planning process. This pre-approval means you’ll receive a detailed, near-exact price estimate upfront.

Abodu’s team manages the experts needed to advise and complete your project. That includes architects, contractors, city and county officials, and engineers. Abodu also offers a quick shipping option through which it can sometimes deliver a ready-made ADU to your property in 30 days.

Putting your plans into motion 

Bedroom in Spacials One Bedroom ADU
Photo by Spacial

You’ve put a lot of thought, time, and research into adding an ADU to your property. That makes choosing a company that will support your vision, facilitate a seamless process, and produce quality results even more important. You need a turnkey ADU services provider with a team of caring, attentive experts – and a system for quickly, properly getting your ADU in place.

At Spacial, our team of experts can guide you through the entire ADU process from start to finish. Our eco-friendly units arrive in one piece, and we install them in one day – and they’re ready to go shortly afterward. Contact us now so we can start bringing your vision to life – and executing the designs, quality, and experience you’ve long had in mind.