Work with ADU Builders Orange County Residents Trust
ADU.Works is a low-cost, no-compromise ADU builder serving Orange County and the rest of the California area.
Are you a homeowner or investor in the Orange County area looking to add an ADU to your property?
Whether your are looking for a rental unit, a place for family members to stay, or simply extra space for yourself, we can help. Our team of experienced builders and designers will work with you to create the perfect ADU for your needs and budget.
We're the ADU Builders Bay area communities trust
And We’re Out to Create A Living Space That Will Make You Proud.
It doesn’t matter if you’re in San Jose, Oakland, or San Francisco, we’d love to help you build an ADU in the Bay area!

What is an Accessory Dwelling Unit (ADU)?



An accessory dwelling unit is a secondary unit to an existing structure. Property owners normally have an ADU constructed to use as backyard homes, guest rooms, storage spaces, rental properties, and so on.
An ADU can be attached to a primary residence or added to a backyard. In some cases, you can also have a basement or garage conversion, to add living space to your property.
An accessory dwelling unit (ADU) typically serves as a residential building, but a property owner can also use it for other purposes, such as providing guest housing, serving as rental properties, functioning as offices, acting as studios, or serving as storage rooms.
By choosing a pre-engineered ADU builder, you gain access to functional space at a fraction of the cost. We offer pre-designed models that enhance your property and leave a lasting impression. Our beautiful ADUs have impressed many people across Orange County and beyond.



About ADU.Works
Our Story
Many of us live in accessory dwelling units ourselves. That’s how much we believe in ADUs. But as we looked around, we found that many ADUs on the market were too pricey or didn’t have the features we wanted.
- Plus, the construction process and customer service weren’t as good as they should be.
- Construction times were longer than expected.
- •Customers had to obtain permits themselves.
We wanted to improve things, so we put together an ADU builder team with experience in construction, project management, design, surveying, restoration, and engineering to create the most beautiful and affordable ADUs in Orange County and the rest of the state of California.
You may see a lot of prefab ADU builders out there… But none like us. We use the best technology possible to come up with quality PRE-ENGINEERED ADUs that have beautiful interior finishes and cost-effective designs and utilize Structural Insulated Panels and Helical Piles to finish faster and be less invasive than traditional builders.
Our Guarantee to You
As an ADU builder out to provide the best ADU services, we commit to help you:



Build an ADU in the Bay area that will be beautiful and cost-effective



Provide only the best client service



Use only reliable and quality materials



Adhere to sustainable practices



Use our expertise to build ADUs that maximize your property space



Find the most cost-effective plan possible
Why You Should Own a Bay Area ADU



Building an ADU in Orange County is a stellar idea for many reasons. Here are just some of the multitudes an ADU brings.
- ADUs raise the property value of an existing space
- Give you a way to earn rental income
- Great for multi-family properties that want to expand their space
- They declutter your main house
- They're more affordable than primary homes
- Give your growing family enough space to live comfortably
- Provide more housing to the people in the region
- Encourage multi-generational living and keep loved ones close
- Reduce housing costs
- Practice sustainable living
- Have more space for all your stuff
What You Can Do With Your ADU




Wondering what you can do with your own ADU? Here are some of the common use-cases for ADUs.
- Accommodate retired parents or other family members
- Turn it into a rental unit for additional income
- Turn your unit into a guest house
- Create a detached office space
- Use it for storage
- Create a caretaker's quarters
- Turn it into a music studio
- House adult children who are job hunting or are in between careers
- Live in it while you're doing a house remodeling project on your main home
- Create a backyard cottage
Check Out Our ADU Models
What Makes Us and Our Units Different



We don’t like to brag, except when we’re talking about our amazing team. We truly believe we have the best ADU builders in the Bay area. We know what it takes to make reliable and beautiful ADUs for our clients.
Everyone from the project manager to the structural engineers behind your new ADU will provide our best work that we can provide to Bay area residents and homeowners.
Our ADUs are designed to blend seamlessly with your existing property and are built to the highest standards of quality and energy efficiency. We use only the quality materials and construction techniques, so you can be sure your ADU will stand the test of time.
Our ADU Building Process
01 Initial Consultation
During the Discovery Call, we will get to know you and your ADU needs. Our ADU Specialist will provide you with an overview of our models and processes and schedule a showroom visit to discuss the next steps.
02 Site Assessment
Our team will conduct a site assessment to determine the feasibility and placement options for your ADU, including evaluating site-specific costs. We will also research your property’s jurisdiction and permit requirements and include this information in the feasibility report. This report will also provide an estimate of the total cost of the ADU on your property.
03 Feasibility Report & Estimated Cost
After the site assessment, we’ll create a feasibility report to guide the following of the build process. The report will provide an estimated additional cost based on our base cost of the unit and include a layout of the proposed ADU, along with an estimate of any site-specific work needed to complete the project. Additionally, the report will be used to prepare the engineering of your ADU.
04 Build Agreement
Once you’ve decided to move forward, we will provide you with a Build Agreement that outlines the entire process from pre-development and engineering to the delivery of your ADU. This will include specific site-specific costs, the estimated timeline to complete the project, fee schedules, permit requirements, and the estimated cost of your ADU.






Places in California We Serve
- San Francisco
- San Jose
- Oakland
- Marin
- East Bay
- Hayward
- Silicon Valley
- And More
Frequently Asked Questions
According to the UC Berkeley Center for Community Innovation, the median construction cost of an ADU in Orange County is about $200 per square foot. (link to source)
However, this figure could vary based on different aspects of your ADU project. But one thing we do aim to do at ADU.Works is give you the best ADU design at the lowest cost possible without compromising on quality. We also do our best to make the most of every square foot of your property.
The maximum size of your ADU will depend on the type of ADU you're planning to create and the size of your property. The maximum size of a detached ADU could be different than the maximum size of an attached ADU.
There's no minimum size to construct an ADU in Orange County. However, homeowners might want to provide as much space as they can so their ADU will be comfortable to live in.
The number of ADUs allowed can also vary depending on the size of your lot, what type of ADU you plan to build, and how many properties you already have on it. But if you have a single-family property already standing on your property, you can probably have one or two permitting you have enough room to build.
Homeowners can use a home equity loan, construction loans, cash-out refinancing, credit card or personal loan to build their property. To learn more about your financing options, you can reach out to our loan specialist here.
To see what requirements we'll need to prepare to get your ADU up, check out the Orange County website.
Here are a few of the most common types of ADUs you can build in Orange County.
Detached ADU
Build ADUs that stand completely on their own. A detached ADU can be a backyard ADU or any other structure where the living space doesn’t share a wall or roof with the primary residence.
Attached ADU
Build attached ADUs to expand your current living space. An attached ADU will share at least one wall and a roof with your primary house.
Garage Conversion
Turn an existing garage into a beautiful attached garage conversion ADU. Garage conversions are a great way to maximize unused garages.
Basement Conversion
Do you have an unused or underutilized basement in your house? Turn that into a living space you can house family members in or rent for extra income.