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Top 7 ADU Construction Companies in Downey, CA

Explore the top 7 ADU construction companies in Downey, CA.
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Top 7 ADU Construction Companies in Downey, CA

Adding an Accessory Dwelling Unit or ADU to your property is a great way to maximize space and add value to your home. Whether you’re thinking about a rental unit or a comfortable in-law suite, finding the right contractor is key.

Here’s a rundown of the top seven ADU construction companies in Downey, CA, that can help bring your project to life.

Bright ADU with floor-to-ceiling windows, hardwood floors, and a cozy window seat for relaxation.

1. Cornejos Builders ADU Construction & Home Building

At Cornejos Builders, we love making your ADU vision come to life. With over five years of experience, we’ve gotten really good at building spaces that not only fit your needs but also feel like a natural extension of your home. 

Whether you’re dreaming up a cozy in-law suite or a rental unit for extra income, we’ve got you covered from the very first design sketch to the final inspection. We’re all about using high-quality materials and smart, energy-efficient solutions to give your ADU a long, low-maintenance life. 

Plus, with our clear pricing and step-by-step communication, you’ll always know what’s happening and what to expect. It’s all about making the process smooth and stress-free, while turning your ideas into a space that feels just right.

Exterior view of a minimalist small construction featuring sleek gray walls and modern white glass door framed in a simple white frame. The clean lines and minimalist design of the windows add to the contemporary aesthetic of the structure, creating a sleek and stylish facade that blends seamlessly with modern architectural principles.
Exterior view of a modern house with gray siding and expansive, contemporary-style windows. The gray siding offers a sleek and sophisticated aesthetic, while the large windows allow ample natural light into the living space, blending functionality with modern design.

See What Our Satisfied Clients Are Saying!

We are very thankful for the positive reviews from our happy customers. Their feedback shows our commitment to quality and inspires us to keep working hard. Take a look at what people are saying about us:

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Marco Urbana

Rated 5 out of 5

Really good and professional company. I love the fact that they are bilingual several companies came our to give a estimate but they were by far the most qualified and did a great job.

Andrei Hienadz

Andrei Hienadz

Rated 5 out of 5

I had a fantastic experience with Cornejos Builders! They exceeded my expectations in every way. From the initial consultation to the final walkthrough, their professionalism and craftsmanship shone through.

Ready to get started? Let’s make your dream ADU a reality – reach out to us at (562) 319-3178 today!

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2. Build My ADU

Build My ADU offers exceptional services for those seeking to add an ADU to their home in Southern California. They focus on creating modern spaces that fit seamlessly into your property. 

Their professional approach ensures a high-quality finish, making them a reliable choice for homeowners looking for additional living space or rental income.

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paul ramirez

Rated 5 out of 5
Working with the Build My ADU company has been great. Tony, Preston, and Keith were all very helpful in explaining the whole build process.

3. Leli Construction, Inc

Known for their expertise in custom pools and construction, Leli Construction extends their knowledge into ADU builds, providing customized designs and efficient construction services. They specialize in making the most of small spaces, creating ADUs that maximize both functionality and style.

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Kevin Ramirez

Rated 5 out of 5
Choosing Leli Construction to bring my backyard dreams to life was one of the best decisions I’ve ever made. From our first phone call, they made me feel like more than just another project—they genuinely listened to my ideas, understood my vision, and worked alongside me every step of the way.

4. ADU Company

ADU Company is a trusted name in the community, offering years of experience in ADU construction. Whether you’re looking to add an in-law suite or an extra rental unit, their team focuses on delivering high-quality designs and efficient project completion.

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Malakai Aarav

Rated 5 out of 5
ADU Company Downey-CA was highly professional and provided the shortest timeline for any service. Ask for a free consultation and estimate, you won’t be disappointed!

6. ADU Room Addition Contractor

With over three years of experience in home building, ADU Room Addition Contractor excels at providing professional and efficient ADU construction services. They are well-versed in garage conversions and other home expansions, ensuring that every project meets client expectations.

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Steve Parker

Rated 5 out of 5
The highest praise for Ivan. Last week completed the construction of a three-bedroom and two-bath ADU detached from our primary house. From the initial estimate to the completion of the dwelling, they were very professional and the results truly surpassed our expectations.

5. Esco Builders Inc.

Esco Builders Inc. specializes in ADU construction and room additions. With over three years in the business, they are known for their attention to detail and high level of craftsmanship. Their experience in ADUs makes them a solid choice for anyone looking to add additional living space to their property.

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J F Real Estate

Rated 5 out of 5
Escobuilders are very talented at building the adu or addition that you need. They do high quality work at a competitive price and are very straight forward.

7. Manny Walls

For over a decade, Manny Walls has been helping homeowners in Downey convert garages into functional ADUs. Their expertise in maximizing space, combined with their commitment to delivering on-time projects, makes them a popular choice for ADU builds in the area.

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Sandra Levin

Rated 5 out of 5
Outstanding. Professional, prompt, reliable, honest. Doesn’t get any better than this. Hire this guy and don’t waste your time.
Types of ADUs In Downey, CA

Build Your ADU with Cornejos Builders

Whether you’re looking to create additional rental income or provide a space for family, these top ADU construction companies in Downey are equipped to help you achieve your goals. With trusted expertise and proven results, your dream ADU is within reach.

And if you’re looking for a seamless, stress-free experience, Cornejos Builders is ready to bring your vision to life. With our dedication to high-quality craftsmanship, clear communication, and a seamless building process, we’ll make sure your ADU is completed to the highest standards.

Contact Cornejos Builders at (562) 319-3178 to start your ADU project in Downey today!

ADU Construction FAQs in Downey, CA

Cornejos Builders offers premier, turnkey ready ADU solutions across our service areas in Southern California, including Orange County. We operate as an “all in one stop” company, taking care of the entire process from permits, architectural design, plumbing, and electrical work. Our comprehensive service ensures you receive a fully equipped ADU ready for immediate use upon completion

Traditional ADU construction costs generally vary from $80,000 up to $250,000.00 depending on the size and scope of work involved. We always recommend requesting a complimentary quote to determine the most realistic price for your specific upgrade

The final price of an ADU hinges heavily on factors such as the size of the unit and design complexity. Generally, cost-effective options often involve converting an existing structure, such as utilizing a garage or basement area (Conversion ADUs) to create a separate living unit. Additionally, Junior Accessory Dwelling Units (JADUs), which are restricted to a maximum size of 500 square feet, may also present a cost-effective choice for creating extra living space

Yes! You’ll get a 1-year warranty on all new ADUs built by us, and the materials warranty on all materials that we’ll buy and use. On top of that, you’ll always have our support, so whenever you need us again, you’ll have priority over anyone else.

Determining whether it is more cost-effective to undertake a large home addition/remodel or build a new ADU hinges on the condition of the home currently being remodeled. The benefit of building a new construction (such as a detached ADU) is the flexibility to design and customize the entire unit to perfectly match your needs, style, and preferences without being constrained by an existing structure

Accessory Dwelling Units (ADUs) in Southern California typically cost between $80,000 to $250,000, with the price fluctuating based on the project’s complexity and size. For instance, past projects include a 535 sq. ft. ADU in Whittier quoted at $150,000, and a larger 798 sq. ft. ADU in Downey quoted at $200,000. We advise consulting with experts to establish a realistic budget and receive a precise price estimate rather than relying on rough estimations

Downey, CA, is a vibrant city blending history and progress. Located in Los Angeles County, it features iconic spots like the world’s oldest operating McDonald’s, a symbol of American fast-food culture. The Columbia Memorial Space Center adds to Downey’s aerospace legacy by providing space science education. The city harmoniously combines its past with a vision for the future.