Avorino / Accessory dwelling units
Orange County, CaliforniaMake room for what comes next.
A separate home. A place for family. More possibility on the property you already own. ADU design and construction, managed together.
The Avorino approach
An ADU should feel like a home in its own right—with privacy, natural light, and a layout that makes everyday living easy.
We bring design, engineering, permits, and construction into one conversation. From the first site visit to the final walk-through, the details stay connected.
What is an ADU?Find your fit
Use this to narrow your options. Then we’ll walk you through which type your lot can take — setbacks, soils, and the overlays your city adds.
Not sure which fits? We’ll review your site and help you choose.
Explore your cost range
Built by Avorino · Brea, California
One real conversion, photographed on site from the first day to the finished kitchen.
The original garage: exposed rafters, old shelving, and a bare slab.
Built by Avorino · Brea, California
One real conversion, photographed on site from the first day to the finished kitchen.
The original garage: exposed rafters, old shelving, and a bare slab.
Rebar laid over a vapor barrier inside the stripped shell.
Concrete poured for the new living floor.
The garage-door opening framed in and sheathed.
Bathroom partitions framed, with drain and supply rough-ins.
Insulation in, and the first drywall hung.
Shower tile set around a black-trim niche.
Process
We handle every step in-house, from design to the build.
01 / 05
Setbacks, easements, utility lines, neighbor friction reviewed together. We tell you what your vision can carry before drawings.
Your lot and goals, reviewed together
02 / 05
We turn your vision into a buildable blueprint — architectural set, structural engineering, soils when needed.
Architecture & engineering, aligned
03 / 05
We take care of the submission, comments, and resubmittal to the city. You sign once and we manage it from there.
A clear path to breaking ground
04 / 05
Foundation, framing, mechanical, electrical, and plumbing, finishes. Weekly progress reports throughout.
From foundations to the final detail
05 / 05
Final inspection, owner walk-through, then the tiered warranty (1-year fit & finish, 4-year systems, 10-year structural).
Final walk-through, warranty, and keys
Recent builds
Explore completed Avorino projects, photographed as built. Different properties, personal priorities, and ways to make a home.
01 / 08
Plan with perspective
What could your ADU cost?
Instant cost-range read on your ADU — calibrated to your city, square footage, finish level, and ADU type.
Planning guidance, not a construction quote.
What could your ADU return?
Project rental income, payback period, and long-term return on your ADU — modeled on real Orange County rents.
Illustrative scenario, not a guaranteed return.
Planning ranges are starting points, not a quote. Your lot, design, and city requirements set the final scope.
An ADU (accessory dwelling unit) is a permitted, self-contained second home on a lot that already has a house: its own kitchen, its own full bath, and its own entrance. California state ADU law recognizes four typologies: detached (standalone, 500–1,200 sqft), attached (built off the primary residence), Junior ADU (converted inside the existing footprint), and garage conversion (an existing garage rebuilt as living space).
A Junior ADU is a conversion inside the existing footprint of the primary house: typically an unused interior wing or bedroom, 300–500 sqft, one bedroom, with a kitchenette and full bath. It's the tightest-scope path in Orange County, typically $135K–$220K+ over 4–6+ months, because no new foundation or exterior structure is involved.
A garage conversion turns an existing garage into permitted living space: insulation, a conditioned envelope, and a full kitchen and bath, usually 350–600 sqft as a studio or one bedroom. In Orange County it typically runs $85K–$170K+ over 4–6+ months, and it's the fastest move when the existing garage frame is sound and you're ready to give up the parking.
Detached ADUs, attached ADUs, Junior ADUs, and garage conversions, every permitted typology under California state ADU law.
Detached: 5–8+ months. Attached: 5–8+ months. Junior ADU: 4–6+ months. Garage conversion: 4–6+ months. Windows vary with city, plan-check timing, and finish-level decisions.
Detached ADUs typically run $245K–$440K+. Attached ADUs $200K–$350K+. Junior ADUs $135K–$220K+. Garage conversions $85K–$170K+. Use the Avorino cost estimator for a calibrated range on your specific project.
Three things matter most in Orange County: a California General-B license (Avorino holds #1107538), design + structural engineering + permitting handled in-house so nothing is lost between separate firms, and a fixed-price contract. Avorino keeps all of it under one roof across 37 OC cities, so your ADU is contracted and built by one company, not coordinated across subs.
No. Avorino handles design, structural engineering, Title 24 calculations, and permitting in-house. Single point of accountability from concept through final inspection.
Avorino builds custom, site-built ADUs, not factory modules. If you're comparing prefab ADUs in Orange County, compare the total installed cost rather than the factory price: foundation, utility connections, crane or transport access, site work, and permits are typically added on top. Prefab pencils best on flat, open lots where a stock plan already fits; on the sloped, tight, or view-sensitive lots common across OC, custom site-built usually delivers better fit and finished value.
Any licensed general contractor can take the job, but ADU work is its own discipline. State ADU law, city-by-city overlays, setback and height exceptions, utility-connection rules, and layouts that actually rent are where budgets slip when a contractor is learning on your project. Avorino runs design, structural engineering, Title 24, permitting, and construction under one roof across 37 Orange County cities, on one fixed-price contract.
Your next chapter starts here
Send the address and your ADU idea. Avorino will review it and follow up with clear next steps.
Free ADU consultation
Tell us where you are in the process. Plans and files are welcome, never required.
Questions
Detached ADUs typically run $245K to $440K+. A detached ADU is a standalone unit on your property with the most rental upside, longest schedule, and biggest ROI when the property has the room.
Detached ADUs typically run $245K to $440K+, attached ADUs $200K to $350K+, Junior ADUs $135K to $220K+, and garage conversions $85K to $170K+. Planning ranges are starting points, not a quote, and your lot, design, and city requirements set the final scope.
We provide a tiered warranty after final inspection: 1-year fit and finish, 4-year systems, and 10-year structural.