About Us
Built for Today.Designed for Tomorrow.
NewGen ADU Builders is a family-owned ADU builder in Cerritos, serving Los Angeles and Orange County and backed by a 1-year workmanship warranty.
01 — Meet the Owner
Meet AntonioCastillo
Antonio Castillo founded NewGen ADU Builders in 2026 with a simple idea: ADU construction should be honest, transparent, and committed to the people paying for it.
As a family-owned business based in Cerritos, NewGen treats each project like the neighbor's house it often is. Garage conversions, storage room conversions, and new attached and detached units are the whole business, so every detail gets the attention it deserves.
Founder, NewGen ADU Builders
Licensed Contractor
Fully Insured & Bonded
Based in Cerritos, CA
02 — How We Work
How We Work
- 01
Consult
When you reach out, you get a free ADU property and investment analysis: a review of your site conditions, access, and utilities, plus your goals and budget. It takes minutes and gives both of us a clear starting point.
- 02
Design
We develop the concept — size, layout, and finish level — and coordinate architectural and engineering work based on the final scope, then deliver a written estimate you review and approve. No surprises.
- 03
Permit
We submit for plan check and coordinate every permit requirement with the applicable jurisdiction so your project is fully approved before construction starts.
- 04
Build
From foundation and framing through MEP and finishes, we manage the defined scope, selections, and schedule, with inspections at every stage, and keep you updated as it progresses.
- 05
Turnover
Final inspection, punch-list completion, and a complete handoff of your finished ADU. Then we stand behind the work with a 1-year workmanship warranty.
03 — Credentials
Licensed, Insured& Bonded
NewGen ADU Builders is a licensed contractor and carries full insurance and bonding, so your property is protected from the first day of work to the last. Documentation is available on request.
Licensed Contractor
Fully Insured
Bonded
1-Year Workmanship Warranty
04 — Get Started
Your ADU StartsWith a Conversation.
Text or call us and we will set up a short intake call, then schedule an on-site visit to walk the project with you. No pressure, no obligation.
- Family owned and operated
- Licensed, insured and bonded
- 1-year workmanship warranty
- Text us at (562) 308-6040, Monday to Friday, 8am to 6pm
05 — FAQ
Common Questions
How long has NewGen ADU Builders been in business?
NewGen ADU Builders was founded in 2026 and is based in Cerritos. We are a new company built around one focus, accessory dwelling units, and around a simple promise: honest, transparent work that we stand behind with a 1-year workmanship warranty.
Are you licensed and insured?
Yes. We are a licensed contractor and are fully insured and bonded. See the credentials section above, and ask us for documentation any time.
Do you only build ADUs?
Yes. Garage conversions, storage room conversions, new ground-up units, and attached and detached ADUs are our entire business. That focus is why the details get the attention they deserve.
What areas do you serve?
We work within about 30 miles of Cerritos across Los Angeles County and Orange County. If you are near the edge of that range, reach out and we will confirm.
How do I get started?
Text or call (562) 308-6040 or send the contact form. We will set up a short intake call and then schedule an on-site visit.
What should I compare when I'm getting bids from other ADU builders?
Before you compare bids, compare scope. Ask every builder to spell out, in writing, who is responsible for design and engineering, utility and electrical-service work, and foundation and structural scope; what cabinet, counter, flooring, and tile allowances are included; who handles permit and inspection responsibilities and site concrete, drainage, and exterior work; what the change-order process and exclusions are; and what your completion, punch-list, and warranty responsibilities look like. We put all of it in writing before you sign.
06 — Service Area
Proudly Serving Cerritosand Surrounding Areas
NewGen ADU Builders is based in Cerritos and serves properties within roughly 30 miles across Los Angeles County and Orange County. If your city is not listed, reach out and we will confirm coverage.
Cerritos, CA
Norwalk
Lakewood
Bellflower
Buena Park
Downey
Whittier
Fullerton
Long Beach
Garden Grove
Proudly serving Cerritos, Los Angeles County, and Orange County. Reach out today to get started.