10 Best ADU Construction Companies In La Habra, CA
If your house is bursting at the seams, an ADU gives everyone room to breathe without having to move out.
Building an ADU is a big decision, and the contractor you pick determines whether you end up with a space your family actually enjoys or a project that drags on for months longer than promised.
Homeowners near La Habra City Hall and around the Children’s Museum at La Habra are adding ADUs for aging parents, adult kids, rental income, and home offices.
Whatever your reason, the right builder handles permits, keeps you informed, and delivers a space built to last.
1. Cornejos Builders
Cornejo’s Builders builds ADUs, home additions, and garage conversions across Southern California, including Downey, San Marino, Rancho Palos Verdes, Newport Beach, and La Habra.
Here’s what stands out about Cornejos Builders:
- Turnkey ADUs from $80,000 to $250,000, depending on size and scope
- Owner showing up personally for consultations, something that’s rare once a company grows past a certain size
- Built in as few as 90 days once the scope is finalized
- 1-year warranty on every new ADU, plus manufacturer warranties on materials
- 3D design included in the process
- Full permitting and planning handled for you, including everything the city requires
- Only local, vetted tradesmen on your property, no rotating subs
- Past projects on record, including a 735 sq. ft. two-story ADU in Alhambra, a 535 sq. ft. turnkey ADU in Whittier, and a 798 sq. ft. ADU in Downey
The company handles the entire process in-house, from design through permitting to final walkthrough, so homeowners aren’t left coordinating anything on their own.
Projects typically move quickly once details are locked in, and the team includes a 3D rendering of your ADU before any materials are ordered, so you can see the space and adjust it before committing to a design.
Wendy Nuno
It was a pleasure to have this company do my company remodel. From the initial call to the finished product, the company was professional and communication was excellent.
They understood the needs of the project and executed it way past my expectations. I would highly recommend them for remodel
Daisy Tapia
Highly observant to detail or changes that others often over look. Gives various options on products and communicates in a professional manner.
I really admire the work ethic.
Call us at (562) 319-3178 or message us here to get your project scoped out.
2. L Square Construction
L Square Construction is a licensed ADU design-build contractor based in Orange County, CA, specializing in accessory dwelling units, garage conversions, home additions, and remodels across Los Angeles and Orange County.
The company handles architecture, permitting, and construction in-house. One of their service-area pages lists La Habra among the cities served.
Efrain G.
I highly recommend L Square Constructions since their team is very attentive with your needs and are always there to explain the process and give you all the details.
One of my friends works there and I can vouch for their efficiency and attention to detail.
Leo R.
I had a great experience working with Brian and Kiko. They helped me plan and build an ADU in my backyard from start to finish.
The team was professional, responsive, and made the whole process smooth and stress-free. Highly recommend if you’re looking to add value to your property or need more living space.
3. Horizon Construction & Remodeling, Inc.
Horizon Construction & Remodeling is a family-owned general contractor based in Fullerton, CA, established in 2009, servicing La Habra.
The company offers kitchen and bathroom remodeling, exterior work, pools, and additions/ADU construction, operating a physical showroom.
Robert C.
We loved our experience with Horizon and David, he was incredible. It was so great to have someone be an advocate for us throughout the entire process and to make sure things were done right when we noticed anything.
David was communicative, patient, and did a fantastic job! Thanks David for everything and we will always recommend you and Horizon to any of our friends and family!
Anastasiia K.
4. AC&R Construction, Plumbing & Electrical
Cathy G.
Antonio M.
5. The ADU Pro
The ADU Pro is an ADU-exclusive design-build contractor based in Chino, CA, founded by DJ Messina, who has over 25 years of construction experience.
It specializes solely in ADUs (detached, attached, garage/JADU, and second-story units) and lists La Habra among its Orange County service cities.
Olasunkanmi O.
After years of dreaming about a poolside guest house, we finally decided to move forward.
The ADU Pro transformed the unused area near our pool into a beautiful retreat for visiting friends and family. Guests constantly tell us they feel like they’re staying at a boutique hotel.
David C.
Excellent customer service, and I am very impressive with how everything turned out! Even down to the finest detail Drecc nailed it.
Couldn’t ask for a better experience truly and industry leader don’t waste your time and money going with anyone else. THESE GUYS ROCK!!!
6. OC Builders Group
OC Builders Group is a design-build firm based in Santa Ana, CA, offering full-service remodeling, home additions, and ADU construction, with a dedicated La Habra service-area page.
Services include garage conversions, 3D design renderings, kitchen and bathroom remodels, and new home construction.
Josh M.
Evan at OC Builders quoted me a very reasonable price and did a great job with basically no oversight. They picked out good materials, appliances, and had a defined vision for the project.
If you want someone who can do the job right without handholding, Evan would be my first call.
Gina C.
7. Avorino Custom Home & ADU
Avorino Custom Home & ADU is an Irvine, CA-based design-build firm, specializing in custom homes, ADUs (detached, attached, JADU, garage conversion), and additions across all 37 Orange County cities, including La Habra.
Founded in 2020, the company reports 7+ years of combined OC construction experience and 150+ completed projects.
Shorouq S.
I am so happy I used Avorino Construction to build and renovate my two custom homes in Santa Ana!! Raja and his team were absolutely amazing and made the whole process seamless and streamlined. Raja uses technology and shared spreadsheets that really helped me stay on track with ordering finishes and the progress of the overall project.
The quality of work was absolutely fantastic and top notch all the way! Raja treated my project as if it was his own and I knew I was definitely in good hands especially in such a highly demanding and stressful project. Absolutely amazing and 10/10 experience.
8. The ADU Company
Patricia D.
The ADU Company put in wood laminate floors in my home as well as a new shower in a bathroom. From start to finish everything was done to our expectations.
Walter and the team he had working on the jobs were very knowledgeable, thorough, and detailed. Walter reviews all work completed and communicated concerns, suggestions and time estimates as the jobs are being in progress.
I truly appreciated the professionalism and quality of the work. We have received many “wow” comments from family and friends!
Peter C.
Unlike contractors I’ve worked with in the past, Walter is honest, timely, and detail oriented. He has completed projects for me and for friends and family and has never disappointed.
If you are looking for an ADU contractors, he’s your man. He was kind enough to work on a few other issues we had in our home. 6- Stars
9. ADU Design & Build
Vina
Super happy with how my new place turned out! The crew was easy to work with, kept me updated, and finished per schedule. The quality is solid and everything looks great.
The total cost was very reasonable and competitive. they built exactly what we requested. Really glad i hired them, they made the whole process way smoother than i expected. I love all details and recommendations they offered.
Steve I.
Farwaz and his team were amazing to work with. They were extra accommodating, even when things went awry on our side.
They serviced us immediately and gave a really great bid, which was the lowest around. Awesome team and really great value! Gonna use for other services soon!
10. ADU West Coast
ADU West Coast is a licensed, vertically-integrated ADU design-build firm headquartered in Seal Beach, CA.
Founded by Cameron Meredith, the company handles the full ADU process in-house. They specialize in garage conversions and backyard ADUs, including rent-share financing options for qualifying homeowners.
Kyle T.
Cameron and his crew at ADU West Coast are professional and do good work. We have referred clients to them that tell me they have received good service.
I haven’t started the process of my ADU yet, but plan to get started when my tenant moves out. ADU West Coast did do a project for my business partner.
They converted a garage to a one bedroom apartment. They also converted a portion of the main house into a studio, known as a Jr. ADU.
I watched the progress of the build and was impressed by their detail and speed. I would recommend these guys to anyone.
Michael B.
We hired ADU West Coast to build a backyard ADU at our Long Beach home and couldn’t be happier.
Cameron and his crew handled everything — permits, design, construction — and finished ahead of schedule. If you’re looking for an ADU contractor in Long Beach, these guys are the real deal.
The Contractor Worth Calling First
Comparing ADU builders is smart. You’re about to spend a meaningful amount of money on a project that’s going to shape how your family lives for years, so it’s worth checking who actually delivers on permitting, timeline, and warranty before you sign anything.
Cornejo’s Builders keeps that process straightforward: one team, a clear price range, a warranty you can point to, and a design you approve before a single wall goes up.
If you’re picturing family dinners in a new space this year, or a parent finally having their own kitchen and bathroom down the hall, that starts with a phone call.
Reach Cornejo’s Builders at (562) 319-3178 or contact them here to get your ADU moving.