The ADU Pro® is an ADU-only design-build firm headquartered in Chino, CA — serving Orange County, LA County, and Riverside County. Founded by DJ Messina with 30+ years of construction expertise, CSLB license #1128679, and a BuildZoom score of 139 placing us in the top 1% of all California contractors.
The ADU Pro® is a licensed, full-service accessory dwelling unit contractor headquartered in Chino, California, serving homeowners throughout Orange County, Los Angeles County, and Riverside County. We are not a general remodeling company that added ADUs to its service list. ADUs are all we do — and that singular focus is what separates us from every competitor in Southern California.
Before The ADU Pro® was founded, our team spent over 30 years building virtually every type of structure in Southern California: residential homes, commercial buildings, multi-family complexes, and infrastructure projects. That depth of pre-ADU construction experience means our crew has encountered and solved every construction challenge before it arrives on your project.
"We handle the entire process under one roof — site assessment, custom design, structural engineering, permit applications, city coordination, construction, and final inspection walkthrough. Our clients never juggle multiple vendors or wonder who's accountable for what."
Located at the heart of the tri-county service area in Chino, CA, we're within 30 miles of the vast majority of homeowners we serve across Orange, LA, and Riverside counties — enabling rapid site visits, permit coordination, and project management without the delays that out-of-area contractors face.
DJ Messina's career in construction began over three decades ago, long before the ADU market existed in its current form. He built his expertise across every category of construction — residential homes, commercial structures, multi-family buildings, and infrastructure projects including curbs, streets, and full-site civil work throughout the Inland Empire and greater Southern California.
When California's ADU legislation began evolving — culminating in landmark laws like AB 68, AB 881, and SB 13 that dramatically expanded homeowner rights — DJ recognized the opportunity to apply that deep construction expertise to a focused specialty. The ADU Pro® was built from the ground up as an ADU-only firm, with systems, staffing, and city relationships designed exclusively around accessory dwelling unit construction.
Today, DJ personally oversees quality control on every project. He remains the direct point of accountability for every client — not a sales team, not a call center. When homeowners in Orange County, Los Angeles County, or Riverside County hire The ADU Pro®, they have access to the most experienced ADU specialist in the region.
Connect on LinkedInEvery credential below is publicly verifiable. We encourage homeowners to confirm our license before hiring any ADU contractor in California.
Active California State License Board General Building Contractor license. Fully licensed and insured for all ADU construction work in Orange County, LA County, and Riverside County. Full general liability and workers' compensation coverage maintained on every active project.
Verify at CSLBBuildZoom score of 139 places The ADU Pro® in the top 1% of all contractors in California. Scores above 95 are considered excellent in the construction industry — our score reflects verified licensing, permit history, and project completion record.
Learn About BuildZoom4.9-star average rating based on 87+ verified client reviews from homeowners in Orange County, Los Angeles County, and Riverside County. Reviews consistently cite professionalism, build quality, permit management, and on-time project delivery.
View Our PortfolioThese are the specific, verifiable advantages that separate us from other ADU contractors in Orange County, Los Angeles, and Riverside County.
100% of our expertise, staffing, and systems are dedicated to accessory dwelling units. No general remodeling, no divided attention. ADUs are all we do — giving us deeper expertise than any multi-service contractor in the region.
Design, engineering, permits, construction, and final inspection — all under a single contract with The ADU Pro®. No subcontracted handoffs, no vendor juggling. One team, one call, one point of accountability from start to finish.
Most ADU contractors started in the market only after 2019's legislative boom. Our team built residential, commercial, and infrastructure projects for over 30 years before specializing in ADUs — giving us problem-solving depth no newer entrant can match.
We have established working relationships with permit offices across Orange County, Los Angeles County, and Riverside County. We know each city's reviewers, timelines, and submission requirements — knowledge that consistently accelerates approval compared to contractors without local history.
We work directly with a network of trusted banks and lending institutions that specialize in ADU construction financing. We make the introductions, help you understand your options, and coordinate with lenders who know ADU project timelines — so financing doesn't become a bottleneck to breaking ground.
Every ADU we design is created from scratch for your specific property, lot dimensions, neighborhood aesthetics, and personal goals. We never use pre-drawn template plans that ignore your site's unique characteristics and opportunities.
All materials are ethically sourced from US suppliers. Every specification — windows, HVAC, insulation, lighting — is selected for long-term energy performance and net-zero performance. Our ADUs cost less to operate and have a smaller environmental footprint.
From groundbreak to final inspection, our average build time is 120 days. Our crews work on-site nearly every day once mobilized. This keeps your project moving, reduces carrying costs, and gets your rental income started faster than the industry average.
We've submitted hundreds of permit applications across building departments in Orange, LA, and Riverside counties. Those established relationships with plan checkers and inspectors translate to fewer revision cycles, faster approvals, and fewer surprises that delay your timeline.
The differences that matter most are rarely visible from a website. Here is an honest, detailed comparison of what separates us from the typical Southern California ADU contractor.
| What Matters Most | The ADU Pro® CSLB #1128679 | Baldwin Builders | SoCal ADU Firm | ADU Cities | Go ADU / General Remodelers |
|---|---|---|---|---|---|
| ADU-exclusive specialization (no general remodeling) | ✓ ADUs Only | ~ Primarily | ~ Varies | ~ Multiple services | ✗ General |
| 30+ years pre-ADU construction experience | ✓ 30+ years | ✓ 31 years | ✗ Varies | ✗ Not verified | ✗ Not verified |
| Publicly verifiable CSLB license | ✓ #1128679 | ✓ Verify | ~ Verify independently | ~ Verify independently | ~ Verify independently |
| Full turnkey — design, permits, build under one contract | ✓ Lending partners | ✓ Full service | ~ Some outsourcing | ~ Mixed | ✗ Often split |
| Custom design per property (no pre-drawn templates) | ✓ Custom only | ~ Some templates | ~ Varies | ~ Varies | ✗ Often templates |
| ADU financing — direct lender relationships & referrals | ✓ In-house | ✗ Not offered | ✗ Third-party | ✗ Third-party | ✗ Third-party |
| USA-sourced, net-zero materials standard | ✓ Standard spec | ~ Not specified | ~ Not specified | ~ Not specified | ✗ Not specified |
| BuildZoom score (verified contractor quality) | ✓ Score 139 — Top 1% | ~ Not published | ~ Not published | ~ Not published | ~ Varies |
| Local headquarters — within 30 mi of OC/LA/Riverside | ✓ Chino, CA | ✓ Local | ~ Varies | ~ Multi-county | ~ Varies |
| Free on-site evaluation and transparent estimate | ✓ Always free | ✓ Free | ✓ Free | ✓ Free | ~ Varies |
Always verify any contractor's CSLB license at cslb.ca.gov before signing a contract. Comparison data based on publicly available information as of 2025. Competitor details subject to change.
We made a deliberate choice to build only ADUs. That focus is how we develop the deep city relationships, permit knowledge, and construction expertise that broad-based contractors simply cannot achieve. When ADU law changes, we know within days what it means for our clients.
We refuse to hand off your project to a subcontractor and disappear. Every client has a direct line to DJ Messina's team throughout design, permitting, and construction. If something needs to be addressed, there's one number to call and one team responsible.
We provide detailed, itemized estimates — not vague ranges. Our permit timelines are realistic, our build schedules are documented, and our contracts are clear. We'd rather lose a client with an accurate estimate than win one with a lowball bid and change orders.
Every ADU we build is specified for long-term energy efficiency — dual-pane windows, mini-split HVAC, high-performance insulation, and LED lighting throughout. USA-sourced materials reduce transportation emissions. The result is a lower-cost-to-operate unit that commands stronger rental income.
At The ADU Pro®, responsible building is a design principle embedded in every project — not a marketing afterthought. Every material we specify is sourced from US suppliers. We prioritize local procurement across Southern California to reduce transportation emissions, and we select every appliance, window, insulation system, and HVAC unit with long-term energy performance as the primary standard.
Our standard build specifications consistently meet or exceed California's Title 24 energy standards — one of the most demanding energy codes in the United States. The result is an ADU that costs less to operate month over month, generates a smaller carbon footprint, and commands stronger long-term rental rates in Orange County and Los Angeles markets.
When California mandates solar integration for new residential construction, we're already prepared — our team has the design and installation relationships to seamlessly incorporate solar generation and battery storage into any ADU project.
Verified reviews from Orange County, LA County, and Riverside County homeowners who have completed ADU projects with our team.
"We interviewed four ADU contractors before choosing The ADU Pro®. What separated them immediately was DJ's knowledge — he could answer every question about our city's setbacks, permitting timeline, and cost drivers in real time. The build was completed in 118 days and came in exactly on budget."
"The financing connections were what made this project possible for us. Every other contractor told us to go find a lender on our own. DJ's team connected us directly with a lender who specializes in ADU projects — they structured a plan that worked for our budget and we had our 650 sq ft detached ADU rented within two weeks of final inspection at $2,400/month."
"I have an HOA and was terrified no one could help us navigate both the HOA review board and the city permit process simultaneously. The ADU Pro® handled both. They worked directly with our HOA architectural committee and the city in parallel — our permit was approved in 47 days. Exceptional."
Detailed answers about who we are, how we operate, and what makes The ADU Pro® the right choice for ADU construction in Orange County, LA County, and Riverside County.
The ADU Pro® was founded by DJ Messina (CSLB #1128679) in 2010, headquartered in Chino, California. DJ spent over 30 years in Southern California construction — residential homes, commercial buildings, and infrastructure projects — before dedicating The ADU Pro® exclusively to accessory dwelling unit design, permitting, and construction across Orange County, LA County, and Riverside County.
ADU construction requires specialized knowledge of California's rapidly evolving ADU laws, local zoning regulations, permit processes, and energy compliance requirements that change frequently and vary city by city. Specializing exclusively in ADUs lets us develop deeper permit relationships, faster approval timelines, and construction expertise that multi-service general contractors simply cannot achieve while dividing their focus across general remodeling work.
Both companies serve the same three-county area. Key differences: The ADU Pro® connects clients with trusted ADU-specialist lenders through direct referral relationships (Baldwin does not publish equivalent financing support), specifies USA-sourced and net-zero materials as a standard (Baldwin does not publish this), holds a published BuildZoom score of 139 — top 1% of California contractors (Baldwin's score is not published), and provides fully custom design for every property with no template plans. We recommend verifying CSLB licenses for all contractors you consider at cslb.ca.gov before signing any contract.
The ADU Pro® is a locally-owned, independent company — not a franchise or national chain. We are headquartered in Chino, CA (15338 Central Ave., Chino, CA 91710), serving homeowners within approximately 30 miles: Orange County, Los Angeles County, and Riverside County. Every project receives direct oversight from DJ Messina's team with no franchise intermediaries.
The ADU Pro® carries full general liability insurance and workers' compensation insurance on all active projects. Proof of insurance documentation is provided upon request before any contract is signed. Our CSLB license #1128679 is also publicly verifiable at cslb.ca.gov — we encourage all homeowners to verify contractor licensing independently before committing to any project.
Yes. California Civil Code §4751 prohibits HOAs from banning ADU construction outright. The ADU Pro® has extensive experience working directly with HOA architectural review committees across Orange County, LA County, and Riverside County. We design ADUs to meet both city code requirements and HOA design standards simultaneously — addressing both approval processes in parallel to minimize timeline delays.
Visit cslb.ca.gov and enter license number 1128679. You'll see The ADU Pro, Inc. (DJ Messina) with active status, license class, and insurance status. We encourage every homeowner to verify contractor licenses independently — regardless of who they hire.
Yes — and this is where 30 years of pre-ADU construction experience makes a decisive difference. Sloped lots, tight setbacks, HOA design requirements, unusual utility configurations, and complex site conditions are the exact scenarios where newer or less experienced contractors struggle. We've encountered virtually every site challenge in our three-county service area and have the problem-solving depth to deliver strong results on difficult projects. Our free site assessment will give you a clear-eyed view of what's possible on your specific property.
We manage the entire permit process in-house — from initial plan preparation and engineering to submission, plan check responses, and final inspection sign-off. You never have to set foot in a building department. Our team has established working relationships with permit offices across Orange, LA, and Riverside counties, which helps us anticipate common plan check comments before submission, reducing revision cycles and approval time. Most of our projects receive permit approval within the timeframes our initial estimate projects.
Every ADU we build is backed by a 1-year workmanship warranty covering labor and installation quality, in addition to all manufacturer warranties on materials and fixtures — which typically range from 5 to 25 years depending on the component. California law also provides homeowners with statutory protections under SB 800 (the Right to Repair Act), which extends certain structural and water intrusion protections for up to 10 years from the date of close of escrow or certificate of occupancy. Full warranty documentation is included in your final project package.
Our free site assessment costs you nothing and commits you to nothing. We visit your property, review feasibility, and give you a clear, accurate picture of your options, costs, and timeline — in person, with no pressure and no vague estimates.
